An efficient implementation of the localized operator partitioning method for electronic energy transfer

TL;DR

This paper presents a computationally efficient implementation of the localized operator partitioning method for defining and analyzing electronic energies within molecular subsystems, enabling detailed studies of electronic energy transfer.

Contribution

The authors reformulate the localized operator partitioning method using a resolution of the identity to simplify integral calculations, improving computational efficiency.

Findings

Applied to A1N molecule, revealing diverse behaviors in excited states.

Enabled detailed analysis of electronic energies and populations in subsystems.

Demonstrated the method's effectiveness for excited state investigations.

Abstract

The localized operator partitioning method [Y. Khan and P. Brumer, J. Chem. Phys. 137, 194112 (2012)] rigorously defines the electronic energy on any subsystem within a molecule and gives a precise meaning to the subsystem ground and excited electronic energies, which is crucial for investigating electronic energy transfer from first principles. However, an efficient implementation of this approach has been hindered by complicated one- and two-electron integrals arising in its formulation. Using a resolution of the identity in the definition of partitioning we reformulate the method in a computationally efficient manner that involves standard one- and two-electron integrals. We apply the developed algorithm to the 9-((1-naphthyl)-methyl)-anthracene (A1N) molecule by partitioning A1N into anthracenyl and CH2-naphthyl groups as subsystems, and examine their electronic energies and populations for several excited states using Configuration Interaction Singles method. The implemented approach shows a wide variety of different behaviors amongst the excited electronic states.