Quantum solvent states of (4He)N-Cs2(3¿u+), 2¿N¿12, clusters

Abstract

Clusters and droplets of noble gases, mainly helium, have opened up a new field of research. In particular, the study of medium-size complexes has been motivated by striking phenomena like superfluidity. It is related with the completely different spectra of molecules embedded in this kind of clusters, depending on the bosonic or fermionic nature of the solvent: in the former case it is a well-defined profile, while in the latter any structure is lost. In this work we study complexes formed by a diatomic Cs2 molecule plus an ensemble of N 4He atoms, with N=2 up to 12. In order to search for the ground state wave-function of the system we have employed a Hartree Quantum-Chemistry-like method, assuming adiabaticity in the diatomic stretch and decoupling of the diatomic rotation from the helium atoms. The PES¿s are described as a pair addition of all the He-He potentials plus anisotropic ab initio He-Cs2 potential. We will show energetic and structural aspects of the clusters, trying to understand the arrangement of the impurity with respect to the helium cloud. Complementary path Integral Monte Carlo calculations at 1 K have also been carried out.