A theoretical study of protonated argon clusters: Ar_nH~+ (n=1-7)

摘要

Molecular geometries and vibrational frequencies of argon shellvated proton clusters obtained at the MP2(full) level of theory using 6-311++G(3df,3pd) basis set are reported. Successive dissociation energies (D_e) and D_0) are calculated at the CCSD(T.full)/6-311++G (3df,3pd)//MP2(full)/6-311++G(3df,3pd) level. A new minimum structure for Ar_2H~+ with bent geometry has been revealed in addition to the known global minimum of the linear isomer. The geometries of the Ar_nH~+ clusters (n>3) provided by the present study are different from those reported in literature. The nature of bonding of Ar-H interactions are discussed based on natural populatio analysis and physical components of the interaction energy decomposition. The consecutive coordination of argon atoms to Ar-H-Ar~+ leads to the weakly increasing consecutive dissociation energies. An analysis of interaction energy component clearly illustrates this anomalous behavior. We notice that a new pattern of argon interactio around proton has emerged on going from Ar_3H~+(C_2v) to Ar_7H~+(D_5h) complexes.