Revealing Ultrafast Population Transfer between Nearly Degenerate Electronic States
journal contributionposted on 2020-02-06, 15:03 authored by Pascal Heim, Sebastian Mai, Bernhard Thaler, Stefan Cesnik, Davide Avagliano, Dimitra Bella-Velidou, Wolfgang E. Ernst, Leticia González, Markus Koch
The response of a molecule to photoexcitation is governed by the coupling of its electronic states. However, if the energetic spacing between the electronically excited states at the Franck–Condon window becomes sufficiently small, it is infeasible to selectively excite and monitor individual states with conventional time-resolved spectroscopy, preventing insight into the energy transfer and relaxation dynamics of the molecule. Here, we demonstrate how the combination of time-resolved spectroscopy and extensive surface hopping dynamics simulations with a global fit approach on individually excited ensembles overcomes this limitation and resolves the dynamics in the n3p Rydberg states in acetone. Photoelectron transients of the three closely spaced states n3px, n3py, and n3pz are used to validate the theoretical results, which in turn allow retrieving a comprehensive kinetic model describing the mutual interactions of these states for the first time.