Signatures of classical bifurcations in the quantum scattering resonances of dissociating molecules

TL;DR

This paper investigates how classical bifurcations influence quantum scattering resonances in dissociating molecules, revealing spectral signatures and proposing a semiclassical method to evaluate resonance properties.

Contribution

It introduces a semiclassical approach based on periodic-orbit theory to analyze quantum resonances affected by classical bifurcations in molecular dissociation.

Findings

Resonance spectra show signatures of classical bifurcations.

Quantum resonances have shorter lifetimes than classical predictions.

A new semiclassical method estimates energy and lifetime of resonances.

Abstract

A study is reported of the quantum scattering resonances of dissociating molecules using a semiclassical approach based on periodic-orbit theory. The dynamics takes place on a potential energy surface with an energy barrier separating two channels of dissociation. Above the barrier, the unstable symmetric-stretch periodic orbit may undergo a supercritical pitchfork bifurcation, leading to a classically chaotic regime. Signatures of the bifurcation appear in the spectrum of resonances, which have a shorter lifetime than classically expected. A method is proposed to evaluate semiclassically the energy and lifetime of the quantum resonances in this intermediate regime.