Modelling of Krn+ clusters IV: Structural changes in Kr3+ and Kr4+

Constant-energy and constant-temperature Monte Carlo simulations have been performed to get insight into temperature-dependent structural changes taking place in the smallest krypton cluster cations, Kr3+ and Kr4+. It is well known that trimers and tetramers form ionic cores of larger rare-gas cluster cations. The two smallest ionic clusters of krypton are thus used to analyze possible structural changes occurring in ionic cores of larger Krn+ clusters. The intra-cluster interactions are described using previously developed diatomics-in-molecules models for the Krn+ clusters with the inclusion of the spin-orbit coupling and the most important three-body non-additivities.