Structures and Energetics of Clusters (n = 5−11)

Ab initio calculations are performed for the clusters, ( n = 5, 7, 9, 11) at the coupled-cluster single-double and quasiperturbative triple excitation (CCSD(T)) level of theory. The use of the correlation-consistent basis sequence aug-cc-pVXZ, with X = D, T, Q, facilitated the estimation of their energies in the complete basis set (CBS) limit. Such hydrogen clusters are constituted by a core in which H 2 units are bound. To understand the features of these bindings, shell structures are examined carefully, and bond dissociation energies, enthalpies, and entropies upon cluster formation are computed and compared with available experimental data.