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Updated: Apr 21, 2026

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Quantum mechanical molecular interactions for calculating the excitation energy in molecular environments: a
Jun-Ya Hasegawa1, Kazuma Yanai, Kazuya Ishimura
1Catalysis Research Center, Hokkaido University, Kita 21, Nishi 10, Kita-ku, Sapporo, 011-0021 (Japan); JST-CREST, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012 (Japan). hasegawa@cat.hokudai.ac.jp.
Abstract:
Intermolecular interactions regulate the molecular properties in proteins and solutions such as solvatochromic systems. Some of the interactions have to be described at an electronic-structure level. In this study, a commutator for calculating the excitation energy is used for deriving a first-order interacting space (FOIS) to describe the environmental response to solute excitation. The FOIS wave function for a solute-in-solvent cluster is solved by second-order perturbation theory. The contributions to the excitation energy are decomposed into each interaction and for each solvent.
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