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koopmans

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.

$ koopmans run silicon.json

New here? Install the code, then run your first calculation.

What you can calculate

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 paramagnetic and magnetic molecules

The LDA and Koopmans band structures of ZnO, with the band gap marked

Band structures of solids, with screening parameters from finite differences or linear response — and with automated Wannierization, for magnetic systems, or with spin-orbit coupling

Predicted against calculated orbital energies, and their error distribution

Screening parameters via machine learning

Placeholder tile for dielectric constants

Dielectric constants, which a Koopmans calculation on a solid needs

Placeholder tile for optical spectra, planned

Optical spectra, from the Bethe-Salpeter equation — planned

Placeholder tile for real-time spectroscopy, planned

Real-time spectroscopy — planned

Citation

If you use this code, please cite [18]. The references page lists the papers behind the functionals themselves.

Indices and Tables