Formation of rubidium dimers on the surface of helium clusters: a first step through quantum molecular dynamics simulations

Starting with separated atoms on the surface of helium clusters 4HeN, and as a first step to assess the formation of rubidium dimers Rb2 in the triplet state, we perform Path Integral Molecular Dynamics simulations in the NVT canonical ensemble. Based on an accurate potential energy surface (PES) for the He–Rb2( 3Σu+ 3Σu+ ) interaction [Guillon et al., J. Chem. Phys. 136, 174307 (2012)], the total PES is analytically described as the addition of pair interactions. The i-PI code [Ceriotti et al., Comput. Phys. Commun. 185, 1019 (2014)] was used to perform the simulations. At a temperature of 2 K, clusters containing up to N = 70 helium atoms, with a number up to 200 beads per particle to describe quantum effects, were considered