##########
 koopmans
##########

.. container:: landing-logo

    .. image:: _static/logo.png
        :width: 400
        :alt: koopmans

.. container:: landing-subtitle

    **accurate and efficient spectral properties of molecules and materials with
    Koopmans functionals**

Koopmans functionals give you orbital energies that can be compared against a
photoemission spectrum — ionization potentials, electron affinities and band structures —
much more cheaply than GW or a hybrid, and just as accurately. These calculations require
a chain of calculations (SCF, Wannierization, linear response, *etc.*), but ``koopmans``
takes care of this: all it needs is an input file describing your system and it will run
everything for you.

.. code-block:: console

    $ koopmans run silicon.json

New here? :doc:`Install the code <installation>`, then run :doc:`your first calculation
<my_first_calculation>`.

************************
 What you can calculate
************************

.. container:: capability-grid

    .. container:: capability-cell

        .. image:: tutorials/orbital_energies/ozone/ozone_spectrum.svg
            :alt: Calculated against experimental binding energies for ozone, with the
                KI points close to the line of perfect agreement and the PBE ones far
                from it

        Orbital energies for :doc:`paramagnetic
        <tutorials/orbital_energies/ozone/index>` and :doc:`magnetic
        <tutorials/orbital_energies/magnetic/index>` molecules

    .. container:: capability-cell

        .. image:: _static/capabilities/zno_bands.png
            :alt: The LDA and Koopmans band structures of ZnO, with the band gap marked

        Band structures of solids, with screening parameters from :doc:`finite
        differences <tutorials/band_structures/silicon_finite_differences/index>` or
        :doc:`linear response <tutorials/band_structures/silicon_linear_response/index>`
        — and with :doc:`automated Wannierization
        <tutorials/band_structures/zno/index>`, for :doc:`magnetic systems
        <tutorials/band_structures/magnetic/index>`, or with :doc:`spin-orbit coupling
        <tutorials/band_structures/spin_orbit/index>`

    .. container:: capability-cell

        .. image:: _static/capabilities/ml_screening.png
            :alt: Predicted against calculated orbital energies, and their error
                distribution

        Screening parameters via :doc:`machine learning
        <tutorials/screening_via_ml/index>`

    .. container:: capability-cell

        .. image:: _static/capabilities/dielectric.svg
            :alt: Placeholder tile for dielectric constants

        :doc:`Dielectric constants <tutorials/dielectric_constants/index>`, which a
        Koopmans calculation on a solid needs

    .. container:: capability-cell planned

        .. image:: _static/capabilities/optical_spectra.svg
            :alt: Placeholder tile for optical spectra, planned

        Optical spectra, from the Bethe-Salpeter equation — *planned*

    .. container:: capability-cell planned

        .. image:: _static/capabilities/realtime.svg
            :alt: Placeholder tile for real-time spectroscopy, planned

        Real-time spectroscopy — *planned*

.. toctree::
    :maxdepth: 2
    :caption: Getting Started
    :name: start
    :hidden:

    installation
    my_first_calculation

.. toctree::
    :maxdepth: 2
    :caption: Background
    :name: background
    :hidden:

    theory
    references

.. toctree::
    :maxdepth: 2
    :caption: User guide
    :name: user_guide
    :hidden:

    input_schema
    cli
    api


.. toctree::
    :maxdepth: 2
    :caption: Tutorials
    :name: tutorials
    :hidden:

    tutorials/orbital_energies/index
    tutorials/band_structures/index
    tutorials/screening_via_ml/index
    tutorials/dielectric_constants/index

**********
 Citation
**********

If you use this code, please cite :cite:`Linscott2023`. The :doc:`references page
<references>` lists the papers behind the functionals themselves.

********************
 Indices and Tables
********************

- :ref:`genindex`
- :ref:`modindex`
- :ref:`search`