Simulated Annealing Study on Structures and Energetics of CO₂ in Argon Clusters

The minimum-energy configurations and energetic properties of the Ar_N-CO₂ (N=1-19) van der Waals clusters were investigated by a simulated annealing algorithm. A newly de-veloped Ar-CO₂ potential energy surface together with the Aziz Ar-Ar interaction potential was employed to construct the high dimensional potential functions by pairwise additive ap-proximation. The global minimal conformations were optimized by sampling the glassy phase space with a circumspectively formulated annealing schedule. Unlike the lighter Rg_N-CO₂ clusters, the size-dependent structural and energetic characteristics of Ar_N-CO₂ exhibit a different behavior. The dramatically variations with number of solvent were found for small clusters. After the completion of the first solvation shell at N=17, the clusters were evolved more smoothly.