CHAPTER 9: Attophotochemistry: Coherent Electronic Dynamics and Nuclear Motion

We describe and discuss the theoretical methodology we use to analyze and predict novel chemical phenomena made possible by attosecond electronic excitation. We describe the dynamics by solving the time dependent Schrödinger equation with the laser pulse treated exactly as part of the Hamiltonian. We include the explicit onset of the nuclear motion following such an ultrafast excitation. The coupling to the nuclei is discussed when using either an adiabatic or a diabatic basis for the electronic dynamics. We begin by analyzing the chemical physics that can be realized by such an ultrafast excitation. Driving chemical reactions specifically towards new channels by selective attosecond excitation is explored as well as the physical parameters that can be used in such a control. Elucidating the role of other variables such as the mass is also discussed. The results are illustrated by recent applications primarily to the N₂, LiH and HCN systems.