Quasi-classical simulations of resonance Raman spectra based on path integral linearization

Hugo Bessone; Rodolphe Vuilleumier; Riccardo Spezia

doi:10.1063/5.0143862

Quasi-classical simulations of resonance Raman spectra based on path integral linearization

J Chem Phys. 2023 Jul 14;159(2):024112. doi: 10.1063/5.0143862.

Authors

Hugo Bessone¹, Rodolphe Vuilleumier¹, Riccardo Spezia²

Affiliations

¹ PASTEUR, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
² Sorbonne Université, Laboratoire de Chimie Théorique, UMR 7616 CNRS, 4 Place Jussieu, 75005 Paris, France.

PMID: 37428056
DOI: 10.1063/5.0143862

Abstract

Based on a linearization approximation coupled with path integral formalism, we propose a method derived from the propagation of quasi-classical trajectories to simulate resonance Raman spectra. This method is based on ground state sampling followed by an ensemble of trajectories on the mean surface between the ground and excited states. The method was tested on three models and compared to a quantum mechanics solution based on a sum-over-states approach: harmonic and anharmonic oscillators and the HOCl molecule (hypochlorous acid). The method proposed is able to correctly characterize resonance Raman scattering and enhancement, including the description of overtones and combination bands. The absorption spectrum is obtained at the same time, and the vibrational fine structure can be reproduced for long excited state relaxation times. The method can also be applied to dissociating excited states (as is the case for HOCl).