Topology-energy relationships and lowest energy configurations for pentagonal dodecahedral (H2O)20X clusters, X = empty, H2O, NH3, H3O+: the importance of O-topology.

摘要: For (H2O)20X water clusters consisting of X enclosed by the 512 dodecahedral cage, X=empty, H2O, NH3, and H3O+, databases are made 55–82 isomers optimized via B3LYP/6-311++G∗∗. Correlations explored between ground state electronic energy (Ee) or plus zero point (Ee+ZPE) clusters’ topology, defined as set directed H-bonds. Linear regression is done to identify topological features that correlate with cluster energy. each X, variables found account for 99% variance in Ee predict it a rms error under 0.2 kcal/mol. The method analysis emphasizes importance an intermediate level structure, “O-topology,” O-types list O pairs bonded but omitting H-bond directions, device organize reduce number structures one needs consider. Relevant include three parameters, which count H-bonds having particular donor acceptor types...