Infrared Gas-phase Intensity Measurements, Polar Tensors, And Effective Charges Of Trans-difluoro- And Trans-dichloroethylene

Abstract

All gas-phase fundamental vibrational intensities of trans-C2H2F2, -C2D2F2, -C2HDF2, -C2H2Cl2 and -C2D2Cl2 have been measured. Isotopic invariance, G sum rule, and quantum chemical information have been used as criteria in selecting preferred experimental values for the dipole-moment derivatives and polar-tensor elements of the Bu (infrared-active) symmetry species of these molecules. The polar tensors of cis-C2H2F2 and -C2H2Cl2 are shown to provide accurate estimates of the vibrational intensities of all the above-mentioned trans-difluoro- and trans-dichloroethylenes, respectively. These polar tensors are also used to calculate the directions of the in-plane dipole-moment derivatives of these molecules. © 1984 American Chemical Society.88352152