Reverse Intersystem Crossing Dynamics in Vibronically Modulated Inverted Singlet-Triplet Gap System: A Wigner Phase Space Study

TL;DR

This study investigates the nuclear and geometric factors influencing the inverted singlet-triplet gap and reverse intersystem crossing rates in a molecular system, emphasizing the role of vibrational dynamics through a phase space approach.

Contribution

It introduces a Wigner phase space method to analyze how nuclear motions affect the INVEST phenomenon and rISC rates, highlighting geometric puckering as a key factor.

Findings

INVEST is present at equilibrium geometry but varies with nuclear geometry.

Nuclear degrees of freedom significantly influence the INVEST and rISC dynamics.

Geometric puckering determines the presence of INVEST and affects transition rates.

Abstract

We inspect the origin of the inverted singlet-triplet gap (INVEST) and slow change in the reverse intersystem crossing (rISC) rate with temperature, as recently observed. A Wigner phase space study reveals, that though INVEST is found at equilibrium geometry, variation in the exchange interaction and the doubles-excitation for other geometries in the harmonic region leads to non- INVEST behavior. This highlights the importance of nuclear degrees of freedom for the INVEST phenomenon and in this case, geometric puckering of the studied molecule determines INVEST and the associated rISC dynamics.