QTAIM Charge-Charge Flux-Dipole Flux Models for the Infrared Fundamental Intensities of Difluoro- and Dichloroethylenes

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• 作者：Joã ; o Vi&ccedil ; ozo da Silva ; Jr. ; Sé ; rgio H. D. M. Faria ; Roberto L. A. Haiduke ; Roy E. Bruns
• 刊名：Journal of Physical Chemistry A
• 出版年：2007
• 出版时间：January 25, 2007
• 年：2007
• 卷：111
• 期：3
• 页码：515 - 520
• 全文大小：81K
• 年卷期：v.111,no.3(January 25, 2007)
• ISSN：1520-5215

文摘

A quantum theory of atoms in molecules (QTAIM) charge-charge flux-dipole flux (CCFDF) decompositionof the MP2/6-311++G(3d,3p) level molecular dipole moment derivatives is reported for the cis-, trans-, and1,1-difluoroethylenes and the cis- and trans-dichloroethylenes. Although the dipole moment derivatives andinfrared fundamental intensities calculated at the MP2 level are overestimated for high-intensity bandscorresponding to CF and CC stretching vibrations, the overall agreement is good with a root-mean-square(rms) error of 19.6 km mol^-1 for intensities ranging from 0 to 217.7 km mol^-1. The intensities calculatedfrom the QTAIM/CCFDF model parameters are in excellent agreement with those calculated directly by theMP2/6-311++G(3d,3p) approach with only a 1.8 km mol^-1 rms error. A high negative correlation (r =-0.91) is found between the charge flux and dipole flux contributions to the dipole moment derivatives.Characteristic values of charge, charge flux, and dipole flux contributions are found for CF, CCl, and CHstretching derivatives. The CH stretching derivatives provide especially interesting results with very highcharge flux and dipole flux contributions with opposite signs. The charge, charge flux, and dipole fluxcontributions are found to be transferable from the cis to the trans isomers providing accurate predictions ofthe theoretical trans intensities with rms errors of 8.6 km mol^-1 for trans-difluoroethylene and 5.9 km mol^-1for trans-dichloroethylene.