title: A Density Functional Study of Methanol Clusters.
abstract: The potential energy surfaces of methanol clusters, (CH3OH)n, n = 2-12, have been studied using density functional theory at the B3LYP/6-31G(d) and higher levels of theory. Cyclic clusters in which n methanol molecules are joined in a ring structure formed by n hydrogen bonds are shown to be more stable than structures of the same number of methanol molecules where one or more methanol molecules are outside the ring and are hydrogen-bonded to oxygens of methanols in rings of n - 1, n - 2, and so forth. So-called chain structures are generally even less stable. Furthermore, the hydrogen-bonding energy per methanol molecule of the n-ring clusters is shown to converge to an asymptotic value of about 27 kJ/mol at B3LYP/6-311+G(d,p)//B3LYP/6-31G(d) after five to six methanols are included in the cluster. As expected, there are many minima on the potential energy surfaces of the methanol clusters, the number increasing rapidly with n. A cyclic cluster of five to six methanol molecules appears to be sufficient to mimic liquid behavior as far as vibrational frequencies are concerned.
authors.affiliation: Department of Chemistry, Mount Saint Vincent University, Halifax, N.S. B3M 2J6, Canada, and Department of Chemistry, Dalhousie University, Halifax, N.S. B3H 4J3, Canada.
authors.forename: Susan L
authors.initials: SL
authors.lastname: Boyd
authors.affiliation: Department of Chemistry, Mount Saint Vincent University, Halifax, N.S. B3M 2J6, Canada, and Department of Chemistry, Dalhousie University, Halifax, N.S. B3H 4J3, Canada.
authors.forename: Russell J
authors.initials: RJ
authors.lastname: Boyd