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    "## Visualizing absorption spectra\n",
    "Absorption spectra can be generated and plotted directly in a Jupyter notebook by using the ``plot_spectrum`` command. The following example computes the first ten excitation energies for water at the CCSD level of theory and plots the spectrum:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
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   "source": [
    "import penguin\n",
    "import veloxchem as vlx\n",
    "\n",
    "xyz_string = \"\"\"\n",
    "    O     0.941414391         0.061806555         0.056540617\n",
    "    H     1.897745723         0.036140170         0.097929548\n",
    "    H     0.668559886        -0.421976725         0.836569836\"\"\"\n",
    "\n",
    "molecule = penguin.get_molecule(xyz_string)\n",
    "basis = penguin.get_molecular_basis(molecule, \"cc-pVDZ\")\n",
    "\n",
    "scf_drv = vlx.ScfRestrictedDriver()\n",
    "scf_drv.ostream.mute()\n",
    "scf_drv.compute(molecule, basis)\n",
    "\n",
    "reference_state = penguin.create_reference_state(molecule, basis, scf_drv)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "ccsd_drv = penguin.CCSD()\n",
    "ccsd_drv.ostream.mute()\n",
    "ccsd_drv.update_settings({\n",
    "    'reference_state': reference_state,\n",
    "    'nstates': 10,\n",
    "    'spectrum': True\n",
    "})\n",
    "ccsd_drv.plot_spectrum('lorentzian', 0.4, 'nm')"
   ]
  }
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