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Application of the charge-charge flux-dipole model to calculate and interpret the infrared intensities of the fluorochlorolethanes

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Author(s):
João Viçozo Silva Junior
Total Authors: 1
Document type: Master's Dissertation
Press: Campinas, SP.
Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Química
Defense date:
Examining board members:
Roy Edward Bruns; Anselmo Elcana de Oliveira; Pedro Antonio Muniz Vazquez
Advisor: Roy Edward Bruns
Abstract

The molecular dipole moments, their derivatives and the fundamental infrared intensities of the fluorochloromethanes are determined from QTAIM atomic charges and dipoles and their fluxes at the MP2/6- 311++G(3d,3p) level. Root-mean-square (rms) errors of 0.01 D and 5.6 km mol are found for the dipole moments and fundamental infrared intensities calculated using QTAIM parameters when compared with those obtained directly from the MP2/6-311++(3d,3p) calculations and 0.04 D and 23.1 km mol when compared to the experimental values. Charge, charge flux and dipole flux contributions are calculated for all the normal vibrations of these molecules. A large negative correlation coefficient of -0.92 is calculated between the charge flux and dipole flux contributions and indicates that charge transfer from one side of the molecule to the other during vibrations is accompanied by relaxation with electron density polarization in the opposite direction. The CF, CCl and CH stretching normal modes of these molecules are shown to have characteristic sets of charge, charge flux and dipole flux contributions. Although the FCF and ClCCl deformation normal modes can also be discriminated from one another based on their sizes and signs of these contributions some HCH deformations have contributions that are similar to those for some of the ClCCl deformations (AU)