Semiclassical "Divide-and-Conquer" Method for Spectroscopic Calculations of High Dimensional Molecular Systems

TL;DR

This paper introduces a semiclassical divide-and-conquer approach that enables quantum vibrational spectra calculations of high-dimensional molecules, successfully capturing anharmonicities and quantum features in complex systems.

Contribution

The paper presents a novel semiclassical divide-and-conquer method for high-dimensional molecular spectroscopy, demonstrating its accuracy on molecules up to 174 vibrational degrees of freedom.

Findings

Accurately reproduces quantum vibrational spectra of small molecules.

Effectively captures quantum anharmonicities and overtones.

Successfully applied to large system C60 with 174 vibrational modes.

Abstract

A new semiclassical "divide-and-conquer" method is presented with the aim of demonstrating that quantum dynamics simulations of high dimensional molecular systems are doable. The method is first tested by calculating the quantum vibrational power spectra of water, methane, and benzene - three molecules of increasing dimensionality for which benchmark quantum results are available - and then applied to C60, a system characterized by 174 vibrational degrees of freedom. Results show that the approach can accurately account for quantum anharmonicities, purely quantum features like overtones, and the removal of degeneracy when the molecular symmetry is broken.