[en] Starting with separated atoms on the surface of helium clusters ⁴He_N, 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(³Σ_u⁺) 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. Graphical abstract: .