Nonzero-temperature vibronic spectra of polyatomic molecules from a zero-temperature classical trajectory
Abstract
By combining coherence thermofield dynamics with the single-Hessian approximation, we enable simulations of low- to medium-resolution vibronic spectra of weakly anharmonic systems at nonzero temperatures, at negligible additional cost relative to zero-temperature calculations. Single-Hessian coherence thermofield Gaussian wavepacket dynamics is exact in any harmonic potential, provided that the reference Hessian is that of the final surface. When applied to Morse systems of increasing anharmonicity and varying temperature, this method successfully captures excited-state anharmonicity and key temperature-dependent spectral features, including hot bands and broadening. By combining the method with on-the-fly ab initio dynamics, we demonstrate its utility by computing the absorption spectra of naphthalene, aminocoumarin C450, and phenyl radical, and the photoelectron spectrum of SeO2− . Within the ab initio single-Hessian approximation, after the zero-temperature spectrum is obtained at the cost of classical molecular dynamics (on the order of hours), all nonzero-temperature spectra are computed in seconds.
Versions
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BibTeX
@misc{barbiero2026nonzerotemperature,
title = {{Nonzero-temperature vibronic spectra of polyatomic molecules from a zero-temperature classical trajectory}},
author = {Davide Barbiero and Jiří J. L. Vaníček},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.20075},
eprint = {2608.20075},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.20075},
}
RIS
TY - UNPB
TI - Nonzero-temperature vibronic spectra of polyatomic molecules from a zero-temperature classical trajectory
AU - Davide Barbiero
AU - Jiří J. L. Vaníček
PY - 2026
DA - 2026/08/20
PB - arXiv
DO - 10.48550/arxiv.2608.20075
UR - https://arxiv.org/abs/2608.20075
AB - By combining coherence thermofield dynamics with the single-Hessian approximation, we enable simulations of low- to medium-resolution vibronic spectra of weakly anharmonic systems at nonzero temperatures, at negligible additional cost relative to zero-temperature calculations. Single-Hessian coherence thermofield Gaussian wavepacket dynamics is exact in any harmonic potential, provided that the reference Hessian is that of the final surface. When applied to Morse systems of increasing anharmonicity and varying temperature, this method successfully captures excited-state anharmonicity and key temperature-dependent spectral features, including hot bands and broadening. By combining the method with on-the-fly ab initio dynamics, we demonstrate its utility by computing the absorption spectra of naphthalene, aminocoumarin C450, and phenyl radical, and the photoelectron spectrum of SeO_2^− . Within the ab initio single-Hessian approximation, after the zero-temperature spectrum is obtained at the cost of classical molecular dynamics (on the order of hours), all nonzero-temperature spectra are computed in seconds.
ER -