{
  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\n# Atomization energy\n\nThe following script will calculate the atomization energy of a\nnitrogen molecule.\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Please look at the script\n:download:`../../tutorials/N2.py`:\n\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "from ase import Atoms\nfrom ase.calculators.emt import EMT"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "First, an ``Atoms`` object containing one nitrogen is created and a\nfast EMT calculator is attached to it simply as an argument.\n\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "atom = Atoms('N')\natom.calc = EMT()"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "The total energy for the isolated atom is then calculated\nand stored in the ``e_atom`` variable.\n\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "e_atom = atom.get_potential_energy()"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "The ``molecule`` object is defined, holding the nitrogen molecule at\nthe experimental bond length ``d=1.1`` Angstrom.\n\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "d = 1.1\nmolecule = Atoms('2N', [(0.0, 0.0, 0.0), (0.0, 0.0, d)])"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "The EMT calculator is then attached to the molecule\nand the total energy is extracted into the ``e_molecule`` variable.\n\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "molecule.calc = EMT()\ne_molecule = molecule.get_potential_energy()"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "The atomization energy is the energy required to break the bond,\nmeaning that it is the negative energetic difference between\nthe molecule and twice the single atom's energy.\n\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "e_atomization = -1.0 * (e_molecule - 2 * e_atom)"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Finally we print the relevant energies:\n\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "print(f'Nitrogen atom energy: {e_atom:5.2f} eV')\nprint(f'Nitrogen molecule energy: {e_molecule:5.2f} eV')\nprint(f'Atomization energy: {e_atomization:5.2f} eV')"
      ]
    }
  ],
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      "display_name": "Python 3",
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      },
      "file_extension": ".py",
      "mimetype": "text/x-python",
      "name": "python",
      "nbconvert_exporter": "python",
      "pygments_lexer": "ipython3",
      "version": "3.13.7"
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