A potential energy surface and a trajectory study of photodynamics and strong-field alignment of ClF molecule in rare gas (Ar,Kr) solids
Molecular alignment by a strong nonresonant laser pulse and a subsequent ultrafast pump–probe experiment are investigated by classical molecular dynamics simulations. A tendency to molecular alignment in the solid host in the presence of an intense ultrashort laser field is examined by simulating the external force due to the polarizability - field interaction. The ground state rotational potential of the ClF molecule is evaluated as the key determining factor along with the dynamics. The pump–probe scheme consists of time-delayed excitations X 1Σ+0 → (B 3Π0 or 1Π1) → ionic states of ClF molecule in Ar or Kr crystals. We show the yields of dissociating ClF trajectories and discuss the fate of cage-exiting F atoms as a competing event to geminate recombination. Emphasis is put on the recombining trajectories. We extract the round-trip times and reorientations for the excited state “wave-packet” motion as important parameters for the analysis of the experimental photodynamics, and show the surrounding lattice response to the collisions.