(Invited, Digital Presentation) In silico Photochemical Experiments with Non-Born-Oppenheimer Molecular Dynamics

Abstract

What happens to a molecule once it has absorbed UV or visible light? How does the molecule release or convert the extra energy it just received? Answering these questions clearly goes beyond a pure theoretical curiosity, as photochemical and photophysical processes are central to numerous domains like energy conversion and storage, radiation damages in DNA, or atmospheric chemistry. Different theoretical tools have been developed to address these questions by simulating the excited-state dynamics of molecules [1]. Two examples of such methods include ab initio multiple spawning (AIMS) and trajectory surface hopping (TSH). AIMS describes the dynamics of nuclear wavepackets using adaptive linear combinations of traveling frozen Gaussians [2]. TSH portrays the nuclear dynamics with a swarm of independent classical trajectories that can hop between potential energy surfaces for this task [3].In this talk, I intend to briefly survey some of our recent work aiming at understanding the approximations underlying AIMS [4] and developing new approximate techniques based on the multiple spawning framework [5]. I will also discuss the application of nonadiabatic methods to unravel photochemical and photophysical processes of interest for photovoltaics.