Solvation of metal atoms in quantum clusters: structural and vibrational properties of Hg(H2)12 and Mg(H2)12

Diffusion quantum Monte Carlo (DQMC) simulations are used to study the vibrational ground state of the clusters Hg(H2)12 and Mg(H2)12. In these clusters, the metal atom is located inside, surrounded by a highly delocalized, liquid-like and, for Hg(H2)12, also nearly spherical envelope of hydrogens. However, the wavefunctions of the clusters exhibit traces of icosahedral behavior within the delocalized structure, related to the geometry of the corresponding classical systems. A simple model wavefunction is fitted, with excellent agreement to the numerical DQMC data. It provides a convenient interpretation of the vibrational ground state of these clusters.