Transferability of the cis- and trans-Dichloroethylene Atomic Polar Tensors

Abstract

The isotopic invariance criterion, ab initio molecular orbital results, and principal component analysis are used to resolve the sign ambiguities of the dipole moment derivatives for cis-dichloroethylene and the out-of-plane derivatives of trans-dichloroethylene. Atomic polar tensors (APTs) for cis-C2H2Cl2 and cis-C2D2Cl2 as well as out-of-plane polar tensor elements for trans-C2H2Cl2 and trans-C2D2Cl2 are reported. Mean dipole moment derivatives of the difluoro- and dichloroethylenes are compared and interpreted as atomic charges. The APTs of cis-dichloroethylene are transferred to trans-dichloroethylene to calculate its infrared fundamental vibrational intensities. These intensities are in much better agreement with the experimental intensities than those calculated by a MP2/6-311++G(d,p) wave function. The transferability of mean dipole moment derivatives between the cis and trans-dichloroethylenes is demonstrated using a simple potential model and carbon and chlorine core electron binding energies obtained by ESCA spectroscopy.