Excitation Energies from the Single-Particle Green's Function with the GW Approximation.

Published

Journal Article

Quasi-particle energies are important in predicting molecular ionization energies and bulk band structures. The state-of-the-art method for quasi-particle energy calculations, particularly for bulk systems, is the GW approximation. For excited state calculations, one needs to go beyond the GW approximation. The Bethe-Salpeter equation (BSE) is the commonly used approach for bulk-system excited state calculations beyond the GW approximation, which is accurate but computationally cumbersome. In this Article, we develop a new method to extract excitation energies directly from the quasi-particle energies based on the GW approximation. Starting from the ( N - 1)-electron system, we are able to calculate molecular excitation energies with orbital energies at the GW level for HOMO excitations. Our calculations demonstrate that this method can accurately capture low-lying local excitations as well as charge transfer excitations in many molecular systems. Our method is shown to outperform the time-dependent density functional theory (TDDFT) and are comparable with higher level excited state calculations, including the equation-of-motion couple cluster (EOM-CC) theory and the BSE, but with less computational effort. This new approach provides an efficient alternative to the BSE method for accurate excited state calculations.

Full Text

Duke Authors

Cited Authors

  • Jin, Y; Yang, W

Published Date

  • April 2019

Published In

Volume / Issue

  • 123 / 14

Start / End Page

  • 3199 - 3204

PubMed ID

  • 30920830

Pubmed Central ID

  • 30920830

Electronic International Standard Serial Number (EISSN)

  • 1520-5215

International Standard Serial Number (ISSN)

  • 1089-5639

Digital Object Identifier (DOI)

  • 10.1021/acs.jpca.9b02379

Language

  • eng