diff --git a/examples/example.fcidump b/examples/example.fcidump
new file mode 100644
index 0000000..4e0331f
--- /dev/null
+++ b/examples/example.fcidump
@@ -0,0 +1,115 @@
+ &FCI NORB=   4,NELEC= 4,MS2=0,
+  ORBSYM=1,1,1,1,
+  ISYM=1,
+ &END
+ 0.3499742123097077    1    1    1    1
+ -2.498001805406602e-16    1    1    2    1
+ 0.3187342023639617    1    1    2    2
+ -0.05760857527185771    1    1    3    1
+ -1.110223024625157e-16    1    1    3    2
+ 0.3220240709613745    1    1    3    3
+ 1.387778780781446e-16    1    1    4    1
+ -0.05991995008750695    1    1    4    2
+ -6.938893903907228e-18    1    1    4    3
+ 0.3621561856539379    1    1    4    4
+ -2.914335439641036e-16    2    1    1    1
+ 0.1642654175746083    2    1    2    1
+ 4.163336342344337e-17    2    1    2    2
+ -5.551115123125783e-17    2    1    3    1
+ 0.06981328566162441    2    1    3    2
+ 2.012279232133096e-16    2    1    3    3
+ -0.0304856292338336    2    1    4    1
+ 6.938893903907228e-17    2    1    4    2
+ 0.1683938036450707    2    1    4    3
+ -4.85722573273506e-16    2    1    4    4
+ 0.3187342023639616    2    2    1    1
+ 1.387778780781446e-17    2    2    2    1
+ 0.332316870291691    2    2    2    2
+ 0.01754743835178967    2    2    3    1
+ 1.387778780781446e-16    2    2    3    2
+ 0.3353562107746392    2    2    3    3
+ 8.326672684688674e-17    2    2    4    1
+ 0.0152359076849083    2    2    4    2
+ 8.326672684688674e-17    2    2    4    3
+ 0.3306045769036404    2    2    4    4
+ -0.05760857527185767    3    1    1    1
+ -6.245004513516506e-17    3    1    2    1
+ 0.01754743835178967    3    1    2    2
+ 0.1276194809490623    3    1    3    1
+ 1.665334536937735e-16    3    1    3    2
+ 0.01816042619236698    3    1    3    3
+ -8.326672684688674e-17    3    1    4    1
+ 0.129061412900203    3    1    4    2
+ -3.747002708109903e-16    3    1    4    3
+ -0.06015443486773168    3    1    4    4
+ -1.318389841742373e-16    3    2    1    1
+ 0.06981328566162442    3    2    2    1
+ 1.665334536937735e-16    3    2    2    2
+ 1.665334536937735e-16    3    2    3    1
+ 0.1460718360858071    3    2    3    2
+ -6.938893903907228e-17    3    2    3    3
+ 0.1039908809723566    3    2    4    1
+ 3.469446951953614e-17    3    2    4    2
+ 0.07291782739227803    3    2    4    3
+ -3.261280134836397e-16    3    2    4    4
+ 0.3220240709613745    3    3    1    1
+ 2.081668171172169e-16    3    3    2    1
+ 0.3353562107746392    3    3    2    2
+ 0.01816042619236699    3    3    3    1
+ -1.110223024625157e-16    3    3    3    2
+ 0.3420576807178073    3    3    3    3
+ -2.775557561562891e-16    3    3    4    1
+ 0.01784240987907962    3    3    4    2
+ 2.914335439641036e-16    3    3    4    3
+ 0.3351920397593786    3    3    4    4
+ 1.52655665885959e-16    4    1    1    1
+ -0.0304856292338336    4    1    2    1
+ 8.326672684688674e-17    4    1    2    2
+ -8.326672684688674e-17    4    1    3    1
+ 0.1039908809723566    4    1    3    2
+ -2.567390744445674e-16    4    1    3    3
+ 0.123330670470909    4    1    4    1
+ -2.983724378680108e-16    4    1    4    2
+ -0.0305887632454903    4    1    4    3
+ 8.326672684688674e-17    4    1    4    4
+ -0.05991995008750692    4    2    1    1
+ 8.326672684688674e-17    4    2    2    1
+ 0.01523590768490828    4    2    2    2
+ 0.1290614129002031    4    2    3    1
+ 4.85722573273506e-17    4    2    3    2
+ 0.01784240987907961    4    2    3    3
+ -2.983724378680108e-16    4    2    4    1
+ 0.1321793953169099    4    2    4    2
+ -2.498001805406602e-16    4    2    4    3
+ -0.06336384545113198    4    2    4    4
+ -2.081668171172169e-17    4    3    1    1
+ 0.1683938036450707    4    3    2    1
+ 1.318389841742373e-16    4    3    2    2
+ -3.747002708109903e-16    4    3    3    1
+ 0.07291782739227805    4    3    3    2
+ 2.844946500601964e-16    4    3    3    3
+ -0.0305887632454903    4    3    4    1
+ -2.498001805406602e-16    4    3    4    2
+ 0.175364225960666    4    3    4    3
+ -2.289834988289385e-16    4    3    4    4
+ 0.3621561856539378    4    4    1    1
+ -4.996003610813204e-16    4    4    2    1
+ 0.3306045769036404    4    4    2    2
+ -0.0601544348677317    4    4    3    1
+ -3.05311331771918e-16    4    4    3    2
+ 0.3351920397593786    4    4    3    3
+ 1.110223024625157e-16    4    4    4    1
+ -0.06336384545113199    4    4    4    2
+ -2.498001805406602e-16    4    4    4    3
+ 0.3791549038771729    4    4    4    4
+ -1.138312749838361    1    1  0  0
+ 4.440892098500626e-16    2    1  0  0
+ -1.046210689921655    2    2  0  0
+ 0.09232698471396558    3    1  0  0
+ 2.775557561562891e-16    3    2  0  0
+ -0.9826377000736198    3    3  0  0
+ 8.326672684688674e-17    4    1  0  0
+ 0.07411836288065318    4    2  0  0
+ -1.387778780781446e-16    4    3  0  0
+ -0.972184230939295    4    4  0  0
+ 1.146550777804458  0  0  0  0
diff --git a/examples/molkit.ipynb b/examples/molkit.ipynb
index 3baab91..dfe756d 100644
--- a/examples/molkit.ipynb
+++ b/examples/molkit.ipynb
@@ -4,179 +4,827 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Molkit"
+    "# Tutorial: Molkit\n",
+    "\n",
+    "## Introduction\n",
+    "This tutorial will be focus in tools available in the new ModelHamiltonian module to manipulate molecular hamiltonians."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### 1. Instantiating a Molecular Hamiltonian"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": 1,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "<moha.molkit.hamiltonians.MolHam object at 0x7e5f1d197560>\n"
+     ]
+    },
+    {
+     "name": "stderr",
+     "output_type": "stream",
+     "text": [
+      "/workspaces/ModelHamiltonian/moha/molkit/hamiltonians.py:179: UserWarning: Duplicate entries in the FCIDUMP file are ignored\n",
+      "  data = load_fcidump(open(path, 'r'))\n"
+     ]
+    }
+   ],
    "source": [
-    "# import libraries\n",
     "import numpy as np\n",
     "from moha import HamHeisenberg\n",
+    "from moha.molkit.hamiltonians import MolHam\n",
+    "\n",
+    "# load a hamiltonian from the fcidump file\n",
+    "hami = MolHam()\n",
+    "hami.from_fcidump('example.fcidump')\n",
+    "print(hami)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### 2. Converting the Hamiltonian to the Spin-Orbital Basis\n",
     "\n",
-    "J_eq = np.array([[0, 1],\n",
-    "                 [1, 0]])\n",
-    "J_ax = np.array([[0, 0.5],\n",
-    "                 [0.5, 0]\n",
-    "                 ])\n",
+    "You can easily perform this conversion by using the `spinize_H` method, which returns the one-body and two-body integrals in the spin-orbital basis.\n",
     "\n",
-    "mu = np.zeros(2)\n",
+    "#### Conversion Rules\n",
     "\n",
-    "ham = HamHeisenberg(J_eq=J_eq, J_ax=J_ax, mu=mu)\n",
-    "one_body = ham.generate_one_body_integral(dense=True)\n",
-    "two_body = ham.generate_two_body_integral(dense=True)"
+    "- *One-body term:*\n",
+    "  - The spatial one-body integral is mapped to the spin-orbital basis as:\n",
+    "    - $h_{pq}^{\\alpha\\alpha} = h_{pq}^{\\beta\\beta} = h_{pq}^{\\text{spatial}}$\n",
+    "    - $h_{pq}^{\\alpha\\beta} = h_{pq}^{\\beta\\alpha} = 0$\n",
+    "\n",
+    "- *Two-body term:*\n",
+    "  - The spatial two-body integral is mapped as:\n",
+    "    - $V_{pqrs}^{\\alpha\\alpha\\alpha\\alpha} = V_{pqrs}^{\\alpha\\beta\\alpha\\beta} = V_{pqrs}^{\\beta\\alpha\\beta\\alpha} = V_{pqrs}^{\\text{spatial}}$"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": 2,
    "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "One-body integrals (spin basis):\n",
+      " [[-1.13831275e+00  4.44089210e-16  9.23269847e-02  8.32667268e-17\n",
+      "   0.00000000e+00  0.00000000e+00  0.00000000e+00  0.00000000e+00]\n",
+      " [ 4.44089210e-16 -1.04621069e+00  2.77555756e-16  7.41183629e-02\n",
+      "   0.00000000e+00  0.00000000e+00  0.00000000e+00  0.00000000e+00]\n",
+      " [ 9.23269847e-02  2.77555756e-16 -9.82637700e-01 -1.38777878e-16\n",
+      "   0.00000000e+00  0.00000000e+00  0.00000000e+00  0.00000000e+00]\n",
+      " [ 8.32667268e-17  7.41183629e-02 -1.38777878e-16 -9.72184231e-01\n",
+      "   0.00000000e+00  0.00000000e+00  0.00000000e+00  0.00000000e+00]\n",
+      " [ 0.00000000e+00  0.00000000e+00  0.00000000e+00  0.00000000e+00\n",
+      "  -1.13831275e+00  4.44089210e-16  9.23269847e-02  8.32667268e-17]\n",
+      " [ 0.00000000e+00  0.00000000e+00  0.00000000e+00  0.00000000e+00\n",
+      "   4.44089210e-16 -1.04621069e+00  2.77555756e-16  7.41183629e-02]\n",
+      " [ 0.00000000e+00  0.00000000e+00  0.00000000e+00  0.00000000e+00\n",
+      "   9.23269847e-02  2.77555756e-16 -9.82637700e-01 -1.38777878e-16]\n",
+      " [ 0.00000000e+00  0.00000000e+00  0.00000000e+00  0.00000000e+00\n",
+      "   8.32667268e-17  7.41183629e-02 -1.38777878e-16 -9.72184231e-01]]\n",
+      "Two-body integrals (spin basis):\n",
+      " [[[[ 3.49974212e-01 -2.91433544e-16 -5.76085753e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-2.91433544e-16  1.64265418e-01 -6.24500451e-17 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-5.76085753e-02 -6.24500451e-17  1.27619481e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[-2.91433544e-16  3.18734202e-01 -1.31838984e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 1.64265418e-01  1.38777878e-17  6.98132857e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-6.24500451e-17  1.75474384e-02  1.66533454e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[-5.76085753e-02 -1.31838984e-16  3.22024071e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-6.24500451e-17  6.98132857e-02  2.08166817e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 1.27619481e-01  1.66533454e-16  1.81604262e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  ...\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  3.18734202e-01\n",
+      "    -1.31838984e-16 -5.99199501e-02]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.38777878e-17\n",
+      "     6.98132857e-02  8.32667268e-17]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.75474384e-02\n",
+      "     1.66533454e-16  1.29061413e-01]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ... -1.31838984e-16\n",
+      "     3.22024071e-01 -2.08166817e-17]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  6.98132857e-02\n",
+      "     2.08166817e-16  1.68393804e-01]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.66533454e-16\n",
+      "     1.81604262e-02 -3.74700271e-16]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ... -5.99199501e-02\n",
+      "    -2.08166817e-17  3.62156186e-01]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  8.32667268e-17\n",
+      "     1.68393804e-01 -4.99600361e-16]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.29061413e-01\n",
+      "    -3.74700271e-16 -6.01544349e-02]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]]\n",
+      "\n",
+      "\n",
+      " [[[-2.91433544e-16  1.64265418e-01 -6.24500451e-17 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 3.18734202e-01  1.38777878e-17  1.75474384e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-1.31838984e-16  6.98132857e-02  1.66533454e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 1.64265418e-01  1.38777878e-17  6.98132857e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 1.38777878e-17  3.32316870e-01  1.66533454e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 6.98132857e-02  1.66533454e-16  1.46071836e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[-6.24500451e-17  6.98132857e-02  2.08166817e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 1.75474384e-02  1.66533454e-16  3.35356211e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 1.66533454e-16  1.46071836e-01 -1.11022302e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  ...\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.38777878e-17\n",
+      "     6.98132857e-02  8.32667268e-17]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  3.32316870e-01\n",
+      "     1.66533454e-16  1.52359077e-02]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.66533454e-16\n",
+      "     1.46071836e-01  4.85722573e-17]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  6.98132857e-02\n",
+      "     2.08166817e-16  1.68393804e-01]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.66533454e-16\n",
+      "     3.35356211e-01  1.31838984e-16]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.46071836e-01\n",
+      "    -1.11022302e-16  7.29178274e-02]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  8.32667268e-17\n",
+      "     1.68393804e-01 -4.99600361e-16]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.52359077e-02\n",
+      "     1.31838984e-16  3.30604577e-01]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  4.85722573e-17\n",
+      "     7.29178274e-02 -3.05311332e-16]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]]\n",
+      "\n",
+      "\n",
+      " [[[-5.76085753e-02 -6.24500451e-17  1.27619481e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-1.31838984e-16  6.98132857e-02  1.66533454e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 3.22024071e-01  2.08166817e-16  1.81604262e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[-6.24500451e-17  1.75474384e-02  1.66533454e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 6.98132857e-02  1.66533454e-16  1.46071836e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 2.08166817e-16  3.35356211e-01 -1.11022302e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 1.27619481e-01  1.66533454e-16  1.81604262e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 1.66533454e-16  1.46071836e-01 -1.11022302e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 1.81604262e-02 -1.11022302e-16  3.42057681e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  ...\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.75474384e-02\n",
+      "     1.66533454e-16  1.29061413e-01]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.66533454e-16\n",
+      "     1.46071836e-01  4.85722573e-17]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  3.35356211e-01\n",
+      "    -1.11022302e-16  1.78424099e-02]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.66533454e-16\n",
+      "     1.81604262e-02 -3.74700271e-16]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.46071836e-01\n",
+      "    -1.11022302e-16  7.29178274e-02]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ... -1.11022302e-16\n",
+      "     3.42057681e-01  2.84494650e-16]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.29061413e-01\n",
+      "    -3.74700271e-16 -6.01544349e-02]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  4.85722573e-17\n",
+      "     7.29178274e-02 -3.05311332e-16]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.78424099e-02\n",
+      "     2.84494650e-16  3.35192040e-01]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]]\n",
+      "\n",
+      "\n",
+      " ...\n",
+      "\n",
+      "\n",
+      " [[[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 3.18734202e-01  1.38777878e-17  1.75474384e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-1.31838984e-16  6.98132857e-02  1.66533454e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-5.99199501e-02  8.32667268e-17  1.29061413e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 1.38777878e-17  3.32316870e-01  1.66533454e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 6.98132857e-02  1.66533454e-16  1.46071836e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 8.32667268e-17  1.52359077e-02  4.85722573e-17 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 1.75474384e-02  1.66533454e-16  3.35356211e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 1.66533454e-16  1.46071836e-01 -1.11022302e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 1.29061413e-01  4.85722573e-17  1.78424099e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  ...\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  3.32316870e-01\n",
+      "     1.66533454e-16  1.52359077e-02]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.66533454e-16\n",
+      "     1.46071836e-01  4.85722573e-17]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.52359077e-02\n",
+      "     4.85722573e-17  1.32179395e-01]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.66533454e-16\n",
+      "     3.35356211e-01  1.31838984e-16]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.46071836e-01\n",
+      "    -1.11022302e-16  7.29178274e-02]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  4.85722573e-17\n",
+      "     1.78424099e-02 -2.49800181e-16]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.52359077e-02\n",
+      "     1.31838984e-16  3.30604577e-01]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  4.85722573e-17\n",
+      "     7.29178274e-02 -3.05311332e-16]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.32179395e-01\n",
+      "    -2.49800181e-16 -6.33638455e-02]]]\n",
+      "\n",
+      "\n",
+      " [[[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [-1.31838984e-16  6.98132857e-02  1.66533454e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 3.22024071e-01  2.08166817e-16  1.81604262e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-2.08166817e-17  1.68393804e-01 -3.74700271e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 6.98132857e-02  1.66533454e-16  1.46071836e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 2.08166817e-16  3.35356211e-01 -1.11022302e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 1.68393804e-01  1.31838984e-16  7.29178274e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 1.66533454e-16  1.46071836e-01 -1.11022302e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 1.81604262e-02 -1.11022302e-16  3.42057681e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-3.74700271e-16  7.29178274e-02  2.84494650e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  ...\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.66533454e-16\n",
+      "     1.46071836e-01  4.85722573e-17]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  3.35356211e-01\n",
+      "    -1.11022302e-16  1.78424099e-02]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.31838984e-16\n",
+      "     7.29178274e-02 -2.49800181e-16]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.46071836e-01\n",
+      "    -1.11022302e-16  7.29178274e-02]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ... -1.11022302e-16\n",
+      "     3.42057681e-01  2.84494650e-16]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  7.29178274e-02\n",
+      "     2.84494650e-16  1.75364226e-01]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  4.85722573e-17\n",
+      "     7.29178274e-02 -3.05311332e-16]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.78424099e-02\n",
+      "     2.84494650e-16  3.35192040e-01]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ... -2.49800181e-16\n",
+      "     1.75364226e-01 -2.49800181e-16]]]\n",
+      "\n",
+      "\n",
+      " [[[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [-5.99199501e-02  8.32667268e-17  1.29061413e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-2.08166817e-17  1.68393804e-01 -3.74700271e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 3.62156186e-01 -4.99600361e-16 -6.01544349e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 8.32667268e-17  1.52359077e-02  4.85722573e-17 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 1.68393804e-01  1.31838984e-16  7.29178274e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-4.99600361e-16  3.30604577e-01 -3.05311332e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 1.29061413e-01  4.85722573e-17  1.78424099e-02 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-3.74700271e-16  7.29178274e-02  2.84494650e-16 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [-6.01544349e-02 -3.05311332e-16  3.35192040e-01 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]]\n",
+      "\n",
+      "  ...\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.52359077e-02\n",
+      "     4.85722573e-17  1.32179395e-01]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.31838984e-16\n",
+      "     7.29178274e-02 -2.49800181e-16]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  3.30604577e-01\n",
+      "    -3.05311332e-16 -6.33638455e-02]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  4.85722573e-17\n",
+      "     1.78424099e-02 -2.49800181e-16]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  7.29178274e-02\n",
+      "     2.84494650e-16  1.75364226e-01]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ... -3.05311332e-16\n",
+      "     3.35192040e-01 -2.49800181e-16]]\n",
+      "\n",
+      "  [[ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  0.00000000e+00\n",
+      "     0.00000000e+00  0.00000000e+00]\n",
+      "   ...\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ...  1.32179395e-01\n",
+      "    -2.49800181e-16 -6.33638455e-02]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ... -2.49800181e-16\n",
+      "     1.75364226e-01 -2.49800181e-16]\n",
+      "   [ 0.00000000e+00  0.00000000e+00  0.00000000e+00 ... -6.33638455e-02\n",
+      "    -2.49800181e-16  3.79154904e-01]]]]\n"
+     ]
+    }
+   ],
+   "source": [
+    "one_body_spin, two_body_spin = hami.spinize_H()\n",
+    "print(\"One-body integrals (spin basis):\\n\", one_body_spin)\n",
+    "print(\"Two-body integrals (spin basis):\\n\", two_body_spin)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### 3. Antisymmetrizing the Two-Electron Integrals\n",
+    "\n",
+    "You can apply proper antisymmetrization to the two-electron integrals using the `antisymmetrize` method. \n",
+    "\n",
+    "This ensures the integrals obey the required permutation symmetry for fermionsm following the rule:\n",
+    "$V_{pqrs} = -V_{pqsr} = -V_{qprs} = V_{qpsr}$"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {},
    "outputs": [],
    "source": [
-    "import numpy as np\n",
-    "from moha import HamHeisenberg\n",
-    "from moha.molkit.hamiltonians import MolHam\n",
-    "from moha.molkit.utils.tools import from_geminal\n",
-    "from moha.molkit.utils.spinops import antisymmetrize_two_body\n",
-    "\n",
-    "def from_geminal(two_body_gem, n_orb):\n",
-    "    \"\"\"\n",
-    "    Inverse of MolHam.to_geminal().\n",
-    "\n",
-    "    Parameters\n",
-    "    ----------\n",
-    "    two_body_gem : (n_gem, n_gem) ndarray\n",
-    "        Matrix in the geminal basis.\n",
-    "    n_orb : int\n",
-    "        Number of spin orbitals.\n",
-    "\n",
-    "    Returns\n",
-    "    -------\n",
-    "    V : (n_orb, n_orb, n_orb, n_orb) ndarray\n",
-    "        Fully antisymmetrised two-electron tensor V_{ijkl}.\n",
-    "    \"\"\"\n",
-    "    n_gem = n_orb * (n_orb - 1) // 2\n",
-    "    if two_body_gem.shape != (n_gem, n_gem):\n",
-    "        raise ValueError(f\"Shape mismatch: got {two_body_gem.shape}, expected ({n_gem},{n_gem})\")\n",
-    "\n",
-    "    # Generate flattened pair list exactly like to_geminal\n",
-    "    pairs = [(i, j) for i in range(n_orb) for j in range(i + 1, n_orb)]\n",
-    "    V = np.zeros((n_orb, n_orb, n_orb, n_orb))\n",
-    "\n",
-    "    for A, (i, j) in enumerate(pairs):\n",
-    "        for B, (k, l) in enumerate(pairs):\n",
-    "            val = 0.25 * two_body_gem[A, B]  # undo the factor 0.5 * 4 = 2\n",
-    "\n",
-    "            # Apply antisymmetric filling\n",
-    "            V[i, j, k, l] = val\n",
-    "            V[j, i, k, l] = -val\n",
-    "            V[i, j, l, k] = -val\n",
-    "            V[j, i, l, k] = val\n",
-    "            V[k, l, i, j] = val\n",
-    "            V[l, k, i, j] = -val\n",
-    "            V[k, l, j, i] = -val\n",
-    "            V[l, k, j, i] = val\n",
-    "\n",
-    "    return V\n",
-    "\n",
-    "\n",
-    "J_eq = np.array([[0, 1],\n",
-    "                 [1, 0]])\n",
-    "J_ax = np.array([[0, 0.5],\n",
-    "                 [0.5, 0]])\n",
-    "mu = np.zeros(2)\n",
-    "\n",
-    "ham_hei  = HamHeisenberg(J_eq=J_eq, J_ax=J_ax, mu=mu)\n",
-    "one_body = ham_hei.generate_one_body_integral(dense=True)\n",
-    "two_body = ham_hei.generate_two_body_integral(dense=True)\n",
-    "Molecular_Hamiltonian = MolHam(one_body=one_body, two_body=two_body)\n",
-    "\n",
-    "h1_spin, h2_spin = Molecular_Hamiltonian.spinize_H()\n",
-    "h2_spin = antisymmetrize_two_body(h2_spin)\n",
-    "\n",
-    "reduced = Molecular_Hamiltonian.to_reduced(n_elec=2)"
+    "hami.antisymmetrize()"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "# Energies Tests"
+    "### 4. Converting the Two-Body Term to the Geminal Basis\n",
+    "\n",
+    "The `to_geminal` method converts the two-body term from the spin-orbital basis to the geminal basis.  \n",
+    "You can specify the type of two-body term: `'rdm2'` (two-body reduced density matrix) or `'h2'` (two-body Hamiltonian).\n",
+    "\n",
+    "The Hamiltonian in the geminal basis is obtained by the following formula:\n",
+    "$V_{A B} =\\frac{1}{2}\\left(V_{p q r s}-V_{q p r s}-V_{p q r s}+V_{qprs}\\right)$\n"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": 4,
    "metadata": {},
+   "outputs": [
+    {
+     "ename": "AttributeError",
+     "evalue": "'MolHam' object has no attribute 'to_geminal'",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[31m---------------------------------------------------------------------------\u001b[39m",
+      "\u001b[31mAttributeError\u001b[39m                            Traceback (most recent call last)",
+      "\u001b[36mCell\u001b[39m\u001b[36m \u001b[39m\u001b[32mIn[4]\u001b[39m\u001b[32m, line 1\u001b[39m\n\u001b[32m----> \u001b[39m\u001b[32m1\u001b[39m geminal = \u001b[43mhami\u001b[49m\u001b[43m.\u001b[49m\u001b[43mto_geminal\u001b[49m(two_body_spin, \u001b[38;5;28mtype\u001b[39m=\u001b[33m'\u001b[39m\u001b[33mh2\u001b[39m\u001b[33m'\u001b[39m)\n",
+      "\u001b[31mAttributeError\u001b[39m: 'MolHam' object has no attribute 'to_geminal'"
+     ]
+    }
+   ],
+   "source": [
+    "geminal = hami.to_geminal(two_body_spin, type='h2')"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### 5. Constructing the Reduced 4-Index Hamiltonian Tensor\n",
+    "\n",
+    "The `to_reduced` method returns the reduced 4-index Hamiltonian tensor $k_{pqrs}$ in the spin-orbital basis, given the number of electrons $N$.\n",
+    "\n",
+    "#### Formula\n",
+    "\n",
+    "$$\n",
+    "k_{pqrs} = \\frac{1}{2(N-1)} \\left( h_{pq} \\delta_{rs} + h_{rs} \\delta_{pq} \\right) + \\frac{1}{2} V_{pqrs}\n",
+    "$$\n",
+    "\n",
+    "where:\n",
+    "- $h_{pq}$: one-electron integrals (spin-orbital basis)\n",
+    "- $V_{pqrs}$: two-electron integrals (spin-orbital basis)\n",
+    "- $\\delta_{pq}$: Kronecker delta"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
    "outputs": [
     {
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "E_spin-orbital : 1.004059262354666e-12\n",
-      "E_geminal      : 1.0040474662350293e-12\n"
+      "(8, 8, 8, 8)\n"
      ]
     }
    ],
    "source": [
-    "import numpy as np\n",
-    "from pyscf import fci\n",
-    "from moha.molkit.hamiltonians import MolHam\n",
+    "reduced = hami.to_reduced(n_elec=4)\n",
+    "print(reduced.shape)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### 6. Extracting Spin Blocks from the Two-Body Spin-Orbital Tensor\n",
+    "\n",
+    "After converting the Hamiltonian to the spin-orbital basis, you can extract the main spin blocks from the two-body tensor using the `get_spin_blocks` method, by accesing the dictionaries keys: 'aaaa', 'bbbb', 'abab'"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "dict_keys(['aaaa', 'bbbb', 'abab'])\n"
+     ]
+    }
+   ],
+   "source": [
+    "spin_blocks = hami.get_spin_blocks()\n",
+    "print(spin_blocks.keys())"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### 7. Computing Energy of a system\n",
+    "\n",
+    "In this section, we will compute the ground-state energy of a toy molecular system using the Full Configuration Interaction (FCI) method using the `pyscf` library.\n",
     "\n",
+    "1. Perform an FCI calculation to obtain the wavefunction and reduced density matrices (RDMs).\n",
     "\n",
-    "h_sp = np.array([[1.0, 0.2],\n",
-    "                 [0.2, 1.5]])\n",
+    "1. Compute the energy using both spin-orbital and geminal representations to verify consistency."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "E_spin-orbital : -4.121211958837992\n",
+      "E_geminal      : -4.121211958837991\n"
+     ]
+    }
+   ],
+   "source": [
+    "from pyscf import fci\n",
+    "from moha.molkit.utils.tools import to_geminal\n",
     "\n",
-    "V_sp = np.zeros((2, 2, 2, 2))\n",
-    "V_sp[0, 0, 0, 0] = 0.7\n",
-    "V_sp[1, 1, 1, 1] = 0.6\n",
+    "# One-electron integrals (spatial orbital basis)\n",
+    "h1 = hami.one_body\n",
+    "h2 = hami.two_body\n",
+    "core_energy = hami.zero_body\n",
     "\n",
-    "N_ELEC, n_spin  = 2, 2                  \n",
-    "toy = MolHam(h_sp, V_sp)\n",
+    "N_ELEC, norb  = 4, hami.n_spatial\n",
     "\n",
-    "h_spin, V_spin = toy.spinize_H()           \n",
-    "norb = h_spin.shape[0]\n",
-    "e_fci, ci_vec = fci.direct_spin1.kernel(h_spin, V_spin, norb, N_ELEC, ecore=0.0)\n",
+    "# Perform Full CI calculation\n",
+    "e_fci, ci_vec = fci.direct_spin1.kernel(h1, h2, norb, N_ELEC, ecore=core_energy)\n",
     "rdm1s, rdm2s = fci.direct_spin1.make_rdm12s(ci_vec, norb, N_ELEC)\n",
     "\n",
-    "rdm1 = np.block([\n",
-    "    [rdm1s[0], np.zeros_like(rdm1s[0])],\n",
-    "    [np.zeros_like(rdm1s[1]), rdm1s[1]]\n",
-    "])\n",
-    "\n",
-    "n = norb // 2  # spatial orbitals\n",
-    "rdm2 = np.zeros((2*n, 2*n, 2*n, 2*n))\n",
-    "for i in range(n):\n",
-    "    for j in range(n):\n",
-    "        for k in range(n):\n",
-    "            for l in range(n):\n",
-    "                # αααα\n",
-    "                rdm2[i, j, k, l] = rdm2s[0][i, k, j, l]\n",
-    "                # ββββ\n",
-    "                rdm2[i+n, j+n, k+n, l+n] = rdm2s[2][i, k, j, l]\n",
-    "                # αβαβ\n",
-    "                rdm2[i, j+n, k, l+n] = rdm2s[1][i, k, j, l]\n",
-    "                # βαβα (hermitian transpose of αβαβ)\n",
-    "                rdm2[i+n, j, k+n, l] = rdm2s[1][i, k, j, l]\n",
-    "\n",
-    "H = toy.to_reduced(n_elec=N_ELEC)  # H = h↑ + 0.5 * V\n",
-    "E_spin = np.einsum('pqrs,pqrs', H, rdm2)\n",
-    "H_gem = toy.to_geminal(H, type='h2')\n",
-    "rdm_gem = toy.to_geminal(rdm2, type='rdm2')\n",
-    "E_gem   = np.einsum('pq,pq', H_gem, rdm_gem)\n",
+    "# construct 2-rdm\n",
+    "rdm2s_new = np.zeros((8, 8, 8, 8))\n",
+    "for i in range(4):\n",
+    "    for j in range(4):\n",
+    "        for k in range(4):\n",
+    "            for l in range(4):\n",
+    "                rdm2s_new[i, j, k, l] = rdm2s[0][i, k, j, l] # aaaa\n",
+    "                rdm2s_new[i+4, j+4, k+4, l+4] = rdm2s[2][i, k, j, l] #bbbb\n",
+    "                rdm2s_new[i, j+4, k, l+4] = rdm2s[1][i, k, j, l] #abab\n",
+    "                rdm2s_new[i+4, j, k+4, l] = rdm2s[1][i, k, j, l] #baba\n",
+    "\n",
+    "\n",
+    "\n",
+    "# Convert to reduced form\n",
+    "H = hami.to_reduced(n_elec=N_ELEC)  # H = 0.5 * (h \\outer h)/(N - 1) + 0.5 * V\n",
+    "# Compute the energy in the MO basis\n",
+    "E_spin = np.sum(H * rdm2s_new)\n",
+    "\n",
+    "# Convert to geminal form\n",
+    "H_gem = to_geminal(H, type='h2')\n",
+    "rdm_gem = to_geminal(rdm2s_new, type='rdm2')\n",
+    "\n",
+    "# Energy from geminal formulation\n",
+    "E_gem = np.einsum('pq,pq', H_gem, rdm_gem)\n",
     "\n",
+    "# Print the energies from both formulations\n",
     "print(\"E_spin-orbital :\", E_spin)\n",
     "print(\"E_geminal      :\", E_gem)\n",
-    "assert np.allclose(E_spin, E_gem, atol=1e-10), \"Energies do not match!\""
+    "assert np.allclose(E_spin, E_gem), \"Energies do not match!\""
    ]
   }
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "moha",
+   "display_name": "Python 3",
    "language": "python",
    "name": "python3"
   },
@@ -190,7 +838,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.11.13"
+   "version": "3.12.1"
   }
  },
  "nbformat": 4,
diff --git a/moha/molkit/hamiltonians.py b/moha/molkit/hamiltonians.py
index 11263d0..1d1df5c 100644
--- a/moha/molkit/hamiltonians.py
+++ b/moha/molkit/hamiltonians.py
@@ -5,6 +5,7 @@
     get_spin_blocks,
     upscale_one_body
 )
+from .utils.tools import load_fcidump
 import numpy as np
 
 
@@ -15,7 +16,7 @@ class MolHam:
     in the form of one- and two-electron integrals.
     """
 
-    def __init__(self, one_body, two_body):
+    def __init__(self, one_body=None, two_body=None, zero_body=0):
         """Initialize MolHam with one and two electron integrals.
 
         Parameters
@@ -24,12 +25,19 @@ def __init__(self, one_body, two_body):
             One-electron integrals in spatial orbital basis
         two_body : np.ndarray
             Two-electron integrals in spatial orbital basis
+        zero_body: float
+            Core energy
 
         """
+        self.zero_body = zero_body
         self.one_body = one_body
         self.two_body = two_body
-        self.n_spatial = one_body.shape[0]
-        self.n_spin = 2 * self.n_spatial
+        if self.one_body is not None:
+            self.n_spatial = one_body.shape[0]
+            self.n_spin = 2 * self.n_spatial
+        else:
+            self.n_spatial = None
+            self.n_spin = None
         self.reduced_ham = None
 
     def antisymmetrize(self):
@@ -47,76 +55,10 @@ def get_spin_blocks(self):
         """
         if not hasattr(self, "two_body_spin"):
             raise RuntimeError(
-                "Call .spinize() first to compute spin-orbital form.")
+                "Call .spinize_H() first to compute spin-orbital form.")
 
         return get_spin_blocks(self.two_body_spin, self.n_spatial)
 
-    def to_geminal(self, two_body=None, type='h2'):
-        r"""
-        Convert the two-body term to the geminal basis.
-
-        Parameters
-        ----------
-        two_body : np.ndarray
-            Two-body term in spin-orbital basis in physics notation.
-        type : str
-            ['rdm2', 'h2']. Type of the two-body term.
-            - 'rdm2' : 2 body reduced density matrix
-            - 'h2' : 2 body Hamiltonian
-
-        Returns
-        -------
-        two_body_gem : np.ndarray
-            Two-body term in the geminal basis
-
-        Notes
-        -----
-        Assuming that rdm2 obbey the following permutation rules:
-        - :math:`\Gamma_{p q r s}=-\Gamma_{q p r s}=-\Gamma_{p q s r}
-        =\Gamma_{q p s r}`
-        we can convert the two-body term to the geminal basis
-        by the following formula:
-
-        .. math::
-
-            \Gamma_{p q}=0.5 * 4 \Gamma_{p q r s}
-
-        where:
-        - :math:`\Gamma_{p q}` is the two-body term in the geminal basis
-        - :math:`\Gamma_{p q r s}` is the two-body term in the spin-orbital
-        Hamiltonian in the geminal basis is obtained by the following formula:
-
-        .. math::
-
-        V_{A B}
-        =\frac{1}{2}\left(V_{p q r s}-V_{q p r s}-V_{p q r s}+V_{qprs}\right)
-
-        """
-        n = two_body.shape[0]
-        two_body_gem = []
-
-        # i,j,k,l -> pqrs
-        for p in range(n):
-            for q in range(p + 1, n):
-                for r in range(n):
-                    for s in range(r + 1, n):
-                        if type == 'rdm2':
-                            two_body_gem.append(
-                                0.5 * 4 * two_body[p, q, r, s]
-                            )
-                        elif type == 'h2':
-                            two_body_gem.append(
-                                0.5 * (
-                                    two_body[p, q, r, s]
-                                    - two_body[q, p, r, s]
-                                    - two_body[p, q, s, r]
-                                    + two_body[q, p, s, r]
-                                )
-                            )
-
-        n_gem = n * (n - 1) // 2
-        return np.array(two_body_gem).reshape(n_gem, n_gem)
-
     def spinize_H(self) -> tuple[np.ndarray, np.ndarray]:
         r"""Convert the one/two body terms from spatial to spin-orbital basis.
 
@@ -174,6 +116,9 @@ def spinize_H(self) -> tuple[np.ndarray, np.ndarray]:
         # βαβα
         two_body_spin[n:, :n, n:, :n] = two_body
 
+        self.one_body_spin = one_body_spin
+        self.two_body_spin = two_body_spin
+
         return one_body_spin, two_body_spin
 
     def to_reduced(self, n_elec):
@@ -212,3 +157,22 @@ def to_reduced(self, n_elec):
 
         k = h_upscaled + 0.5 * V_spin
         return k
+
+    def from_fcidump(self, path):
+        """Assign Hamiltonian parameters from an FCIDUMP file.
+
+        Parameters
+        ----------
+        path : str
+            Path to the FCIDUMP file.
+
+        Returns
+        -------
+        None
+        """
+        data = load_fcidump(open(path))
+        self.one_body = data['one_ints']
+        self.two_body = data['two_ints']
+        self.zero_body = data['core_energy']
+        self.n_spatial = self.one_body.shape[0]
+        self.n_spin = 2 * self.n_spatial
diff --git a/moha/molkit/utils/tools.py b/moha/molkit/utils/tools.py
index c3904d7..fad250f 100644
--- a/moha/molkit/utils/tools.py
+++ b/moha/molkit/utils/tools.py
@@ -1,6 +1,74 @@
 r"""Utilities for molecular Hamiltonians."""
 
 import numpy as np
+from warnings import warn
+
+
+def to_geminal(two_body=None, type='h2'):
+    r"""
+    Convert the two-body term to the geminal basis.
+
+    Parameters
+    ----------
+    two_body : np.ndarray
+        Two-body term in spin-orbital basis in physics notation.
+    type : str
+        ['rdm2', 'h2']. Type of the two-body term.
+        - 'rdm2' : 2 body reduced density matrix
+        - 'h2' : 2 body Hamiltonian
+
+    Returns
+    -------
+    two_body_gem : np.ndarray
+        Two-body term in the geminal basis
+
+    Notes
+    -----
+    Assuming that rdm2 obbey the following permutation rules:
+    - :math:`\Gamma_{p q r s}=-\Gamma_{q p r s}=-\Gamma_{p q s r}
+    =\Gamma_{q p s r}`
+    we can convert the two-body term to the geminal basis
+    by the following formula:
+
+    .. math::
+
+        \Gamma_{p q}=0.5 * 4 \Gamma_{p q r s}
+
+    where:
+    - :math:`\Gamma_{p q}` is the two-body term in the geminal basis
+    - :math:`\Gamma_{p q r s}` is the two-body term in the spin-orbital
+    Hamiltonian in the geminal basis is obtained by the following formula:
+
+    .. math::
+
+    V_{A B}
+    =\frac{1}{2}\left(V_{p q r s}-V_{q p r s}-V_{p q r s}+V_{qprs}\right)
+
+    """
+    n = two_body.shape[0]
+    two_body_gem = []
+
+    # i,j,k,l -> pqrs
+    for p in range(n):
+        for q in range(p + 1, n):
+            for r in range(n):
+                for s in range(r + 1, n):
+                    if type == 'rdm2':
+                        two_body_gem.append(
+                            0.5 * 4 * two_body[p, q, r, s]
+                        )
+                    elif type == 'h2':
+                        two_body_gem.append(
+                            0.5 * (
+                                two_body[p, q, r, s]
+                                - two_body[q, p, r, s]
+                                - two_body[p, q, s, r]
+                                + two_body[q, p, s, r]
+                            )
+                        )
+
+    n_gem = n * (n - 1) // 2
+    return np.array(two_body_gem).reshape(n_gem, n_gem)
 
 
 def from_geminal(two_body_gem, n_orb):
@@ -42,3 +110,125 @@ def from_geminal(two_body_gem, n_orb):
             V[l, k, j, i] = val
 
     return V
+
+
+def set_four_index_element(four_index_object, i0, i1, i2, i3, value):
+    """Assign a value to a four-index tensor with 8-fold symmetry.
+
+    Adapted from the IOData library:
+    https://iodata.readthedocs.io/en/latest/index.html
+
+    Assign values to a four-index object, accounting for
+    8‑fold index symmetry.
+    This function assumes physicists' notation.
+
+    Parameters
+    ----------
+    four_index_object : np.ndarray
+        Four-index tensor to modify
+        (shape=(nbasis, nbasis, nbasis, nbasis)).
+    i0, i1, i2, i3 : int
+        Indices of the element to assign.
+    value : float
+        Value of the matrix element to store.
+    """
+    four_index_object[i0, i1, i2, i3] = value
+    four_index_object[i1, i0, i3, i2] = value
+    four_index_object[i2, i1, i0, i3] = value
+    four_index_object[i0, i3, i2, i1] = value
+    four_index_object[i2, i3, i0, i1] = value
+    four_index_object[i3, i2, i1, i0] = value
+    four_index_object[i1, i2, i3, i0] = value
+    four_index_object[i3, i0, i1, i2] = value
+
+
+def load_fcidump(lit) -> dict:
+    """Load integrals from an FCIDUMP file.
+
+    Adapted from the IOData module:
+    https://iodata.readthedocs.io/en/latest/index.html
+
+    Parse the Molpro 2012 FCIDUMP format (restricted wave functions).
+
+    Parameters
+    ----------
+    lit : LineIterator
+        Iterator over lines of the FCIDUMP file.
+
+    Returns
+    -------
+    dict
+        Dictionary with one- and two-electron integrals and core energy.
+        Keys: 'nelec', 'spinpol', 'one_ints', 'two_ints', 'core_energy'.
+
+    Notes
+    -----
+    1. This function works only for restricted wave functions.
+    2. One- and two-electron integrals are stored in chemists' notation
+       in an FCIDUMP file, while IOData and MoHa internally use
+       physicists' notation.
+    3. The FCIDUMP format changed in MOLPRO 2012;
+    older versions are not supported.
+    """
+    # check header
+    line = next(lit)
+    if not line.startswith(" &FCI NORB="):
+        raise (f"Incorrect file header: {line.strip()}", lit)
+
+    # read info from header
+    words = line[5:].split(",")
+    header_info = {}
+    for word in words:
+        if word.count("=") == 1:
+            key, value = word.split("=")
+            header_info[key.strip()] = value.strip()
+    nbasis = int(header_info["NORB"])
+    nelec = int(header_info["NELEC"])
+    spinpol = int(header_info["MS2"])
+
+    # skip rest of header
+    for line in lit:
+        words = line.split()
+        if words[0] == "&END" or words[0] == "/END" or words[0] == "/":
+            break
+
+    # read the integrals
+    one_mo = np.zeros((nbasis, nbasis))
+    two_mo = np.zeros((nbasis, nbasis, nbasis, nbasis))
+    core_energy = 0.0
+
+    for line in lit:
+        words = line.split()
+        if len(words) != 5:
+            raise (
+                f"Expecting 5 fields on each data line in FCIDUMP, "
+                f"got {len(words)}.",
+                lit,
+            )
+        value = float(words[0])
+        if words[3] != "0":
+            ii = int(words[1]) - 1
+            ij = int(words[2]) - 1
+            ik = int(words[3]) - 1
+            il = int(words[4]) - 1
+            if two_mo[ii, ik, ij, il] != 0.0:
+                warn(
+                    "Duplicate entries in the FCIDUMP file are ignored",
+                    stacklevel=2,
+                )
+            set_four_index_element(two_mo, ii, ik, ij, il, value)
+        elif words[1] != "0":
+            ii = int(words[1]) - 1
+            ij = int(words[2]) - 1
+            one_mo[ii, ij] = value
+            one_mo[ij, ii] = value
+        else:
+            core_energy = value
+
+    return {
+        "nelec": nelec,
+        "spinpol": spinpol,
+        "one_ints": one_mo,
+        "two_ints": two_mo,
+        "core_energy": core_energy,
+    }