期刊
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
卷 9, 期 3, 页码 1356-1367出版社
AMER CHEMICAL SOC
DOI: 10.1021/ct3010722
关键词
-
资金
- U.S. Department of Energy, Office of Science, Office of Basic Energy Science through the Combustion Energy Frontier Research Center [DE-SC0001198, DE-FG02-86ER13579]
We present a new approximation for calculating partition functions and thermodynamic functions by the multistructural method with torsional anharmonicity (MS-T). The new approximation is based on a reference potential with torsional barriers obtained from a calculation that includes local torsional coupling. By comparing to a fully coupled classical rotational-torsional partition function evaluated as a numerical phase space integral, the method is shown to provide improved accuracy in the classical limit. Quantum effects, which are most important at low temperatures, are included based on the harmonic approximation (which can be upgraded to a quasiharmonic approximation, that is, harmonic formulas with effective frequencies). Calculations were performed for six molecules (ethanol, 1-butanol, hexane, isohexane, heptane, and isoheptane), one radical (1-pentyl radical), and the saddle point structures of a hydrogen abstraction reaction (hydroxyl plus ethanol) to illustrate the difference between the new coupled-potential MS-T approximation and the original uncoupled-potential MS-T approximation. The new method improves the agreement with experimental results of calcuated thermodynamic functions for 1-butanol, hexane, isohexane, and heptane.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据