Capturing anharmonic effects in single vibronic level fluorescence spectra using local harmonic Hagedorn wavepacket dynamics

• Main Authors: Zhang, Zhan Tong, Visegrádi, Máté, Vaníček, Jiří J. L
• Format: Journal Article
• Language: English
• Published: 21-08-2024
• Subjects: Physics - Chemical Physics; Physics - Quantum Physics
• DOI: 10.48550/arxiv.2408.11991

Hagedorn wavepacket dynamics yields exact single vibronic level (SVL)
fluorescence spectra from any initial vibrational level in displaced, squeezed,
and Duschinsky-rotated global harmonic models. Real molecules, however, have
anharmonic potential energy surfaces. To partially describe effects of
anharmonicity on the spectra, we combine the Hagedorn approach to spectroscopy
with the local harmonic approximation of the potential. We compute the SVL
spectra for several anharmonic Morse-type potentials in one, two, and twenty
dimensions and compare them to the results of global harmonic approximations
and, where possible, of exact quantum calculations. We show that the local
harmonic approach yields more accurate results than global harmonic
approximations, especially for the emission spectra from higher initial
vibrational levels.