Open-boundary cluster model with a parameter-free complex absorbing potential

Kosuke Imamura; Tomokazu Yasuike; Hirofumi Sato

doi:10.1063/5.0184571

Open-boundary cluster model with a parameter-free complex absorbing potential

J Chem Phys. 2024 Jan 21;160(3):034103. doi: 10.1063/5.0184571.

Authors

Kosuke Imamura¹, Tomokazu Yasuike², Hirofumi Sato^{1

3}

Affiliations

¹ Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan.
² Department of Liberal Arts, Faculty of Liberal Arts, The Open University of Japan, Chiba 261-8586, Japan.
³ Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan.

PMID: 38230813
DOI: 10.1063/5.0184571

Abstract

In quantum chemical calculations of heterogeneous structures in solids, e.g., when an impurity is located on the surface, the conventional cluster model is insufficient to describe the electronic structure of substrates due to its finite size. The open-boundary cluster model (OCM) overcomes this problem by performing cluster calculations under the outgoing-wave boundary condition. In this method, a complex absorbing potential (CAP) is used to impose the boundary condition, but the CAP used in the previous studies required parameter optimization based on the complex variational principle. This study proposes and applies a parameter-free CAP to OCM calculations. This approach makes it possible to uniquely determine the band-specific CAP based on the surface Green's function theory. Using this CAP, we conducted OCM calculations of the tight-binding model of a one-dimensional semi-infinite chain, and we found that the calculated density of states agreed with the exact one. Surface states of the Newns-Anderson-Grimley model were also computed using the CAP, and the projected density of states on the adsorbed atom was successfully reproduced.