Eur. Phys. J. B (2018) 91: 137
https://doi.org/10.1140/epjb/e2018-90200-0

Regular Article

Visualizing electronic excitations with the particle-hole map: orbital localization and metric space analysis^★

Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, USA

^a e-mail: ullrichc@missouri.edu

Received: 23 March 2018
Received in final form: 30 April 2018
Published online: 2 July 2018

Abstract

The particle-hole map (PHM) is a computational tool to visualize electronic excitations–calculated using time-dependent density-functional theory–based on representations in canonical molecular orbital transition space. Beyond the standard canonical representation, transformation to localized orbitals is a common technique in electronic structure theory. We analyze the PHM as a visualization tool for both canonical and localized orbital representations and give numerical examples for simple one-dimensional model systems. We show that the localized PHMs can be used to construct simple descriptors of the charge-transfer character of an excitation through metric space analysis, and that it can improve the clarity of the visualization provided by the canonical PHM.