Mapping Ultrafast Structural Dynamics in Photochemistry with Femtosecond Time-Resolved Time-Domain Raman Spectroscopy

Abstract

Photochemical reactions involve the change of the molecular structure, such as rotation, dissociation, and formation of chemical bonds. Real-time observation of such structural rearrangements facilitates understanding the molecular mechanism that underlies the reaction and developing more sophisticated photo-functional molecular systems. While various time-resolved techniques have been developed in this quest in the last decades, it has not yet been trivial to track structural changes of the molecules proceeding on the time scale of the nuclear motion, i.e., femto-to-picosecond time scale. We developed femtosecond time-resolved time-domain Raman spectroscopy using sub-7-fs pulses and enabled tracking structural changes of the molecules on the femtosecond time scale with exquisite sensitivity. In this review, we overview the principle and experimental of the technique and introduce our recent studies on real-time observation of the ultrafast structural dynamics in the primary photochemical/photophysical processes of condensed-phase complex molecular systems.