Understanding of molecular motions in nonadiabatic photoisomerization dynamics of cis-stilbene with on-the-fly simulation of transient absorption pump-probe spectra

Abstract

Theoretical simulations of time-resolved transient absorption spectra, combining on-the-fly trajectory surface hopping with doorway-window formalism, provide a powerful approach to unravel the nonadiabatic dynamics of cis-stilbene. The results show that the key molecular motions driving photoisomerization are captured by the evolution of spectral components, including ground-state bleach, stimulated emission, and excited-state absorption. By establishing a critical link between nuclear dynamics and time-resolved spectral responses, this work demonstrates the essential role of theoretical spectroscopy in decoding ultrafast photochemical processes and offers a predictive framework for mapping molecular dynamics from spectral signatures.