| Abstract
| - The molecular dipole moments, their derivatives, and the fundamental IR intensities of the fluoro-, chloro-,and fluorochloromethanes are determined from QTAIM atomic charges and dipoles and their fluxes at theMP2/6-311++G(3d,3p) level. Root-mean-square (rms) errors of 0.01 D and 5.6 km mol-1 are found for thedipole moments and fundamental IR intensities calculated using QTAIM parameters when compared withthose obtained directly from the MP2/6-311++(3d,3p) calculations and 0.04 D and 23.1 km mol-1 whencompared with the experimental values. Charge, charge flux, and dipole flux contributions are calculated forall the normal vibrations of these molecules. A large negative correlation coefficient of −0.92 is calculatedbetween the charge flux and dipole flux contributions and indicates that electron transfer from one side of themolecule to the other during vibrations is accompanied by relaxation with electron density polarization in theopposite direction. The CF, CCl, and CH stretching normal modes of these molecules are shown to havecharacteristic sets of charge, charge flux, and dipole flux contributions. Although the FCF and ClCCldeformation normal modes can also be discriminated from one another based on the sizes and signs of thesecontributions, some HCH deformations have contributions that are similar to those for some of the ClCCldeformations.
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