koopmans: An Open-Source Package for Accurately and Efficiently Predicting Spectral Properties with Koopmans Functionals.
Edward B LinscottNicola ColonnaRiccardo De GennaroNgoc Linh NguyenGiovanni BorghiAndrea FerrettiIsmaila DaboNicola MarzariPublished in: Journal of chemical theory and computation (2023)
Over the past decade we have developed Koopmans functionals, a computationally efficient approach for predicting spectral properties with an orbital-density-dependent functional framework. These functionals impose a generalized piecewise linearity condition to the entire electronic manifold, ensuring that orbital energies match the corresponding electron removal/addition energy differences (in contrast to semilocal DFT, where a mismatch between the two lies at the heart of the band gap problem and, more generally, the unreliability of Kohn-Sham orbital energies). This strategy has proven to be very powerful, yielding molecular orbital energies and solid-state band structures with comparable accuracy to many-body perturbation theory but at greatly reduced computational cost while preserving a functional formulation. This paper reviews the theory of Koopmans functionals, discusses the algorithms necessary for their implementation, and introduces koopmans, an open-source package that contains all of the code and workflows needed to perform Koopmans functional calculations and obtain reliable spectral properties of molecules and materials.
Keyphrases
- density functional theory
- molecular dynamics
- optical coherence tomography
- solid state
- machine learning
- healthcare
- primary care
- drug delivery
- magnetic resonance
- dual energy
- heart failure
- molecular dynamics simulations
- randomized controlled trial
- clinical trial
- magnetic resonance imaging
- deep learning
- quality improvement
- monte carlo