Ultrafast structural dynamics in electronically excited solid neon. II. Molecular-dynamics simulations of the electronic bubble formation

Mol.-dynamics simulations of structural relaxation in electronically excited NO-doped solid neon are presented. The NO impurity is excited to its lowest A (3ss) Rydberg state, inducing a rearrangement of the surrounding medium in the form of a bubble, due to repulsion between the Rydberg electron and the closed-shell surrounding species. The simulations were carried out using the thermal harmonic quantum correction in order to account for quantum effects. The first shell response is characterized by an initial expansion and an oscillatory response, which point to coherent dynamics and confirm the exptl. obsd. slower dynamics than in solid argon. The medium response is characterized by a collective oscillatory behavior of the shells around the impurity. We investigated the role of quantum effects, nature of the NO-Ne ground- and excited-state potentials and of the Ne-Ne potential on the dynamics. It appears that the expansion stage is mainly detd. by the fact that the repulsive interaction between the excited impurity and the Ne lattice reaches out beyond the first shell, so that the first three shells are simultaneously pushed outward. Combined with the short-range character of the Ne-Ne interaction, this sets in motion a larger mass than in solid argon. The collective response is mainly due to the short-range Ne-Ne interaction and the tight nature of the Ne lattice. Quantum effects play a negligible role in the overall dynamics, at least to the level of approxn. of our simulations. [on SciFinder (R)]