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Updated: Nov 3, 2025

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Reliability of the Phonon Density of States Determined by Real-Coded Genetic Algorithm from Heat Capacities of
1Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550, Japan.
Abstract:
Constant-pressure heat capacities (Cs) of crystalline benzoic acid (BAh) and its deuterated analogue (C6H5COOD, BAd) were measured by adiabatic calorimetry, and the phonon density (g(ω)) of states was determined from their C data using a real-coded genetic algorithm (RCGA) with just generation gap + real-coded ensemble cross-over. The distribution of g(ω) was in reasonable agreement with the spectroscopic one observed for molecular vibration modes, indicating sufficient reliability of g(ω) determined by the RCGA. Based on the fact that Cs reveals an inverse-isotope effect in the temperature range 30-130 K, the determined g(ω)s were used to investigate the molecular mechanism of the effect: g(ω) of BAd revealed blue shifts in the ranges of ω = 80-100 and 150-230 K, as referred to that of BAh. It was suggested from the combined considerations on g(ω) and spectroscopic results that an anticooperative correlation exists between O-H···O hydrogen bonds and interdimer interactions in BA.
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