Boyd Susan L, Boyd Russell J
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.
J Chem Theory Comput. 2007 Jan;3(1):54-61. doi: 10.1021/ct6002912.
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.
已使用密度泛函理论在B3LYP/6 - 31G(d)及更高理论水平下研究了甲醇团簇(CH3OH)n（n = 2 - 12）的势能面。结果表明，由n个甲醇分子通过n个氢键连接成环状结构的环状团簇，比相同数量甲醇分子组成的结构更稳定，在后一种结构中，有一个或多个甲醇分子在环外，并与n - 1、n - 2等环内甲醇分子的氧形成氢键。所谓的链状结构通常更不稳定。此外，在团簇中包含五到六个甲醇分子后，在B3LYP/6 - 311+G(d,p)//B3LYP/6 - 31G(d)水平下，n元环团簇中每个甲醇分子的氢键能收敛到约27 kJ/mol的渐近值。正如预期的那样，甲醇团簇的势能面上有许多极小值，其数量随n迅速增加。就振动频率而言，五到六个甲醇分子的环状团簇似乎足以模拟液体行为。
