Application of the Mixed Time-averaging Semiclassical Initial Value Representation method to Complex Molecular Spectra

TL;DR

This paper demonstrates the application of a semiclassical initial value representation method to complex molecular spectra, accurately capturing vibrational shifts in high-dimensional condensed phase systems without relying on specific potential forms.

Contribution

The study extends the mixed time-averaging semiclassical method to high-dimensional condensed phase models, enabling direct ab initio spectroscopic simulations of complex molecular systems.

Findings

Successfully applied to systems with up to 61 dimensions

Accurately reproduces vibrational blueshift and redshift effects

Does not depend on specific potential forms, broadening applicability

Abstract

The recently introduced mixed time-averaging semiclassical initial value representation molecular dynamics method for spectroscopic calculations [M. Buchholz, F. Grossmann, and M. Ceotto, J. Chem. Phys. 144, 094102 (2016)] is applied to systems with up to 61 dimensions, ruled by a condensed phase Caldeira-Leggett model potential. By calculating the ground state as well as the first few excited states of the system Morse oscillator, changes of both the harmonic frequency and the anharmonicity are determined. The method faithfully reproduces blueshift and redshift effects and the importance of the counter term, as previously suggested by other methods. Differently from previous methods, the present semiclassical method does not take advantage of the specific form of the potential and it can represent a practical tool that opens the route to direct ab initio semiclassical simulation of condensed phase systems.