Nonadiabatic transition paths from quantum jump trajectories

TL;DR

This paper introduces a method combining Transition Path Theory with quantum jump trajectories to analyze rare reactive pathways in open quantum systems, revealing how conical intersection geometry influences relaxation mechanisms.

Contribution

It extends classical reactive path concepts to quantum systems, providing new insights into nonadiabatic dynamics and the role of system geometry in relaxation processes.

Findings

Geometry of conical intersections affects transition state character.

Relaxation pathways depend on diabatic coupling strength.

Method elucidates dominant reactive pathways and rates.

Abstract

We present a means of studying rare reactive pathways in open quantum systems using Transition Path Theory and ensembles of quantum jump trajectories. This approach allows for elucidation of reactive paths for dissipative, nonadiabatic dynamics when the system is embedded in a Markovian environment. We detail the dominant pathways and rates of thermally activated processes, as well as the relaxation pathways and photoyields following vertical excitation in a minimal model of a conical intersection. We find that the geometry of the conical intersection affects the electronic character of the transition state, as defined through a generalization of a committor function for a thermal barrier crossing event. Similarly, the geometry changes the mechanism of relaxation following a vertical excitation. Relaxation in models resulting from small diabatic coupling proceed through pathways dominated by pure dephasing, while those with large diabatic coupling proceed through pathways limited by dissipation. The perspective introduced here for the nonadiabatic dynamics of open quantum systems generalizes classical notions of reactive paths to fundamentally quantum mechanical processes.