Structural, Energetic, and Infrared Spectra Insights into Methanol Clusters (CH3OH)n, for n = 2-12, 16, 20. ONIOM as an Efficient Method of Modeling Larg
详细信息 查看全文
- 作者：Marcos M. Pires ; Vincent F. DeTuri
- 刊名：Journal of Chemical Theory and Computation
- 出版年：2007
- 出版时间：May 2007
- 年：2007
- 卷：3
- 期：3
- 页码：1073 - 1082
- 全文大小：302K
- 年卷期：v.3,no.3(May 2007)
- ISSN：1549-9626
文摘
An investigation of gas-phase methanol clusters (CH3OH)n, where n = 2-12, 16,and 20, was completed with a range of computational methods: PM3, Hartree-Fock, B3LYP,MP2, and their combination using an ONIOM (our own n-layered integrated molecular orbitaland molecular mechanics) method. Geometries, binding energies, and vibrational frequenciesare reported. For all ab initio optimized structures, the cyclic isomer was found to be the moststable structure of all isomers investigated. The scaled OH frequency shift for n = 1-4 is foundto be in good agreement with experimentally measured shifts. An ONIOM method, with themethyl group calculated at the low level and the hydroxyl group at the high level, proved to bean excellent way of reducing computational expense. The calculated enthalpies, geometries,and infrared spectra using an ONIOM method were comparable to that of a high-level calculation.Clusters were solvated using the integral equation formalism for the polarized continuum modelmethod to compare with the microsolvation studies.