Approximate Functionals for Multistate Density Functional Theory

This python package implements approximate multistate matrix functionals for the electron-electron repulsion and the kinetic energy to be used in multistate density functional theory (MSDFT) [1].

The code can be used to reproduce the calculations and figures from the preprint [2] Approximate Functionals for Multistate Density Functional Theory.

Requirements

Required python packages:

• becke-multicenter-integration
• matplotlib, numpy, pandas, psutil, scipy, tqdm
• pyscf

A conda environment with the required packaged can be created with

$ conda env create -f environment.yml
$ conda activate msdft

Installation

The package is installed with

$ pip install -e .

in the top directory. To verify the proper functioning of the code a set of tests should be run with

$ cd tests
$ python -m unittest

Getting Started

An example calculation of LiF is provided in the folder examples/09-lithium-fluoride-lda/. There are scripts for evaluating the LDA-like multistate density functional along the dissociation curve of lithium fluoride.

References

[1]	Yangyi Lu, Jiali Gao, "Multistate Density Functional Theory for Excited States", J. Phys. Chem. Lett. 2022, 13, 7762-7769, https://doi.org/10.1021/acs.jpclett.2c02088

[2]	Alexander Humeniuk, "Approximate Functionals for Multistate Density Functional Theory", ChemRxiv (2024), https://doi.org/10.26434/chemrxiv-2024-xb9jr