Chemical solutions in a quantum solvent: Anionic electrolytes in 4He nanodroplets

Variational and diffusion Monte Carlo (VMC and DMC) calcula- tions are presented for anionic electrolytes solvated in 4He. The electrolytes have the general structure X(He)N, with X = F, Cl, Br and I, and N varying up to 40 (41 for I). The overall interaction potential is obtained from accurate ab initio data for the two- body components and then using the sum-of-potentials approxi- mation. Our computational scheme is a robust procedure, giving us accurate trial wavefunctions that can be used to perform high-quality DMC calculations. The results indicate very marked delocalization and permanence of the liquid-like quantum fea- tures of the solvent adatoms surrounding the anionic impurities. This finding stands in contrast to the more structured, solid-like behavior of the quantum solutions with alkali metal cations em- bedded in He nanodroplets. While other negatively charged spe- cies such as H have shown an overall repulsive interaction with He, the present calculations clearly indicate that the halogen anions remain solvated within liquid-like solvent “bubbles” of species-dependent size.