Solvation of metal atoms in quantum clusters: Structural and vibrational properties of Hg(H-2)(12) and Mg(H-2)(12)

Diffusion quantum Monte Carlo (DQMC) simulations are used to study the vibrational ground state of the clusters Hg(H-2)(12) and Mg(H-2)(12). In these clusters, the metal atom is located inside, surrounded by a highly delocalized, liquid-like and, for Hg(H-2)(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.