Ionization dynamics of Ne-doped helium clusters at low temperature: Ring-polymer molecular dynamics simulations including electronically nonadiabatic transitions

Ionization dynamics of NeHen (n <= 100) clusters has been studied by path-integral molecular dynamics (PIMD) and ring-polymer molecular dynamics (RPMD) simulations that can effectively describe nuclear quantum effects. The pairwise-additive interatomic potential model was used for the neutral NeHen clusters while the diatomics-in-molecule (DIM) model including spin-orbit coupling in Ne+ (P-2) was employed to describe the electronic structures of the cationic NeHen+ clusters. We found that the calculated ionization spectra of NeHen were very similar to those of He-n except for Ne ionization transitions. This indicates that helium density distributions are similar for both the Ne-doped and undoped clusters. The RPMD simulations have been performed to understand the initial charge migration dynamics and its associated nuclear dynamics through the instantaneous ionization of NeHe100. We found that, when the Ne atom is preferentially ionized, the He atoms in the first solvation shell are readily attracted by Ne+ to form a snowball structure.