IR + UV laser pulse control of momenta directed to specific products: Quantum model simulations for HOD* → H + OD versus HO + D

Abstract

Selective bond breaking may be achieved in two steps. First, an intense ultrashort, i.e. few-cycle infrared (IR) laser pulse creates momentum along the bond to be broken. Another ultrashort few-cycle ultraviolet (UV) laser pulse then induces a Franck–Condon (FC)-type transition from the electronic ground to an excited state. The initial bond selective momentum is approximately conserved during this FC-type transition, thus causing a stretch and finally a break in the specific bond. Bond selectivity via few-cycle IR + UV laser pulses can be achieved even if the forces of the excited molecule are not bond selective in the domain of the FC-type transition. The mechanism is demonstrated by means of quantum simulations of IR + UV laser driven wavepackets of the model system, HOD* → H + OD versus HO + D.