Miquel Huix-Rotllant conference

Abstract
Photochemical processes are governed by the interplay between electronic structure, nuclear motion, and the surrounding environment. Understanding and ultimately controlling these processes therefore requires theoretical approaches that can describe excited-state dynamics while accounting for the complexity of condensed-phase systems.
In this seminar, I will present recent developments in my group aimed at addressing this challenge from complementary perspectives. I will first discuss how external electric fields can modify the electronic-state landscape and influence the ultrafast isomerization dynamics of protonated Schiff-base models. I will then discuss QM/MM approaches under periodic boundary conditions for describing photochemical dynamics in realistic environments, with applications to energy redistribution, excited-state relaxation, and redox processes. Finally, I will present the development of efficient electronic-structure methods for excited states, including semi-empirical approaches that make nonadiabatic dynamics accessible for larger molecular systems.
Together, these studies illustrate the need for combining increasingly efficient descriptions of electronic structure and nuclear dynamics with explicit representations of the environment. The goal is to move beyond the description of photochemical reactions in isolated molecular models towards predictive simulations of non-equilibrium processes in complex condensed-phase systems, and to identify the environmental factors that can be exploited to control photochemical reactivity.

Contact
[Boris Le Guennic](https://iscr.univ-rennes.fr/boris-le-guennic), [boris.leguennic@univ-rennes.fr](mailto:boris.leguennic@univ-rennes.fr)