Dissociation dynamics of diatomic molecules in intense laser fields: A scheme for the selection of relevant adiabatic potential curves

摘要

We investigated the nuclear dynamics of diatomic molecular ions in intense laser fields by analyzing theirnfragment kinetic-energy release (KER) spectra as a function of the pump-probe delay τ . Within the Born-nOppenheimer (BO) approximation, we calculated ab initio adiabatic potential-energy curves and their electricndipole couplings, using the quantum chemistry code GAMESS. By comparing simulated KER spectra as a functionnof either τ or the vibrational quantum-beat frequency for the nuclear dynamics on both individual and dipolecouplednBO potential curves with measured spectra, we developed a scheme for identifying electronic statesnthat are relevant for the dissociation dynamics. We applied this scheme to investigate the nuclear dynamics innO2n+ ions that are produced by ionization of neutral O2 molecules in an ultrashort infrared (IR) pump pulse andndissociate due to the dipole coupling of molecular potential curves in a delayed IR probe laser field.