Quasi-particle energy spectra in local reduced density matrix functional theory

TL;DR

This paper demonstrates the application of local RDMFT to larger molecular systems, showing its efficiency and accuracy in predicting electronic spectra and stability, with improvements for large systems and solids.

Contribution

It extends local RDMFT to larger molecules, showcasing its computational efficiency and accuracy, and introduces a new model for fractional occupancies to enhance performance.

Findings

Accurately predicts photoelectron spectra of molecules.

Shows stability trends in C20 isotopes.

Improves efficiency for large systems and solids.

Abstract

Recently, we introduced (e-print arXiv:1407.7128) {\em local reduced density matrix functional theory} (local RDMFT), a theoretical scheme capable of incorporating static correlation effects in Kohn-Sham equations. Here, we apply local RDMFT to molecular systems of relatively large size, as a demonstration of its computational efficiency and its accuracy in predicting single-electron properties from the eigenvalue spectrum of the single-particle Hamiltonian with a local effective potential. We present encouraging results on the photoelectron spectrum of molecular systems and the relative stability of C$_{20}$ isotopes. In addition, we propose a modelling of the fractional occupancies as functions of the orbital energies that further improves the efficiency of the method useful in applications to large systems and solids.