Electron Transfer, Diabatic Couplings and Vibronic Energy Gaps in a Phase Space Electronic Structure Framework

TL;DR

This paper compares a traditional Born-Huang approach with a new phase space framework for electronic structure calculations, showing the latter's improved accuracy in vibronic energy gaps in non-adiabatic regions.

Contribution

The paper introduces a novel phase space electronic Hamiltonian framework that outperforms the Born-Huang method in calculating vibronic properties.

Findings

Phase space framework yields smaller errors in vibrational energy gaps.

Performance advantage is significant outside strongly nonadiabatic regions.

Results suggest potential for improved modeling of electron transfer dynamics.

Abstract

We investigate the well-known Shin-Metiu model for an electronic crossing, using both a standard Born-Huang (BH) framework and a novel phase space (PS) electronic Hamiltonian framework. We show that as long as we are not in the strongly nonadiabatic region, a phase space framework can obtain a relative error in vibrational energy gap and other vibronic matrix elements that are consistently one order of magnitude smaller than what is found within a BH framework. In line with recent results showing that dynamics on one phase space surface can outperform dynamics on one Born-Oppenheimer surface, our results indicate that the same advantages should largely hold for curve crossings and dynamics on two or a handful of electronic surfaces, from which several implications can be surmised as far as the possibility of spin-dependent electron transfer dynamics.