In silico photochemistry

The goal of this Chapter is to provide examples attesting to the maturity of current strategies for simulating the excited-state dynamics and nonradiative processes of molecules in the gas phase. Such progress over the past few decades means that we are approaching the possibility of performing in silico photochemistry, i.e., a photochemical experiment taking place fully on the computer and allowing for the prediction of photochemical processes and observables – at least qualitatively. We provide here a brief survey of nonadiabatic molecular dynamics and the creation of a hierarchy of methods within the multiple spawning framework. We then show how nonadiabatic molecular dynamics techniques can be used in the context of atmospheric photochemistry.