Spin-Polarized Rb2 Interacting with Bosonic He Atoms: Potential Energy Surface and Quantum Structures of Small Clusters

A new hill-dimension potential energy surface of the three-body He-Rb-2(E-3(u)+) complex and a quantum study of small (H-4(e))(N)-Rb-2(E-3(u)+) clusters, 1 <= N <= 4, are presented. We have accurately fitted the ab initio points of the interaction to an analytical form and addressed the dopant's vibration, which is found to be negligible. A Variational approach and a Diffusion Monte Carlo technique have been applied to yield energy and geometric properties of the selected species. Our quantum structure calculations show a transition in the arrangements of the helium atoms from N = 2, where they tend to be separated across the diatomic bond, to N = 4, in which a closer packing of the rare gas particles is reached, guided by the dominance of the He-He potential over the weaker interaction of the latter adatoms with the doping dimer. The deepest well of the He-Rb-2 interaction is placed at the T-shape configuration, a feature which causes the dopant to be located as parallel to the helium minidroplet. Our results are shown to agree with previous findings on this and on similar systems.