The polar tensors, effective charges, and infrared intensities of X2CY molecules

Abstract

Infrared gas phase intensity measurements. Polar tensors and effective charges of cisdichloroethylened 0 and d 2 Infrared gas phase intensity measurements, polar tensors, and effective charges of vinylidene fluoride and its deuterated modificationsThe experimental polar tensors and effective charges for the X 2 CY molecules where X=F,CI and Y =O,S have been calculated. The polar tensors, with the exception of 3Px/iJxy, and the effective charges of anyone of these molecules can be calculated from these values for the other three molecules. The effective charges of carbon, oxygen, and sulfur are not transferable although those for fluorine and chlorine are transferable within the calculated experimental errors. The effective charge values appear to show trends which reflect the electronegativities of the atoms in the molecules. The sums of the gas phase infrared fundamental intensities of these molecules are shown to be interrelated.

QTAIM Charge–Charge Flux–Dipole Flux Interpretation of Electronegativity and Potential Models of the Fluorochloromethane Mean Dipole Moment Derivatives

“…Indeed, sum rules of this nature have been observed for the fluorochloromethanes 4 and also for the X 2 CY (X = F, Cl; Y = O, S) molecules. 5,6 Besides these interesting relations, the carbon mean dipole moment derivatives of the halomethanes and of other molecules obtained from experimental infrared intensities 7 have been shown to obey Siegbahn's simple potential model 8 for the carbon 1s electron ionization energies. Because the simple potential model proposes a linear relation between these energies and atomic charges, the mean derivatives must be closely related to these charges.…”

Quantum Theory of Atoms in Molecules Charge−Charge Flux−Dipole Flux Models for the Infrared Intensities of X2CY (X = H, F, Cl; Y = O, S) Molecules

“…In the 1970s it was shown that the atomic polar tensors determined from the experimental fundamental infrared frequencies and intensities of F 2 CO, Cl 2 CO, F 2 CS, and Cl 2 CS can be related by , for three cases: (1) α 1 = α 3 = Cl; α 2 = α 4 = F; (2) α 1 = α 2 = O α 3 = α 4 = S; (3) α 1 = α 2 = α 3 = α 4 = C. The interpretation of this kind of relation is simple. The effect of substituting F for Cl on the polar tensor elements of the other atoms in the molecule does not depend on whether oxygen or sulfur is the other substituent.…”

“…In the 1970s it was shown that the atomic polar tensors determined from the experimental fundamental infrared frequencies and intensities of F 2 CO, Cl 2 CO, F 2 CS, and Cl 2 CS can be related by 4,5 for three cases:…”

Characteristic Substituent-Shift Models for Carbon 1s Ionization Energies and Mean Dipole-Moment Derivatives

“…At about the same time, studies being made by our research group noted that mean dipole-moment derivatives, p̄ α , obtained from infrared gas-phase fundamental intensities of the X 2 CY (X = F, Cl; Y = O, S) molecules could be related by the equation for three distinct cases: (1) α 1 = α 3 = Cl and α 2 = α 4 = F; (2) α 1 = α 2 = O and α 3 = α 4 = S; and (3) α 1 = α 2 = α 3 = α 4 = C. This result indicates that a model of characteristic group mean dipole-moment derivative shifts also holds for these molecules. Furthermore, a matrix equation analogous to the one above was shown to hold for the atomic polar tensors of these molecules, and a scalar one was also valid for the corresponding infrared intensity sums . Infrared intensity sums of the halomethanes have also been shown to be related by an equation similar to eq 2 …”

“…Furthermore, a matrix equation analogous to the one above was shown to hold for the atomic polar tensors of these molecules, 17 and a scalar one was also valid for the corresponding infrared intensity sums. 18 Infrared intensity sums of the halomethanes have also been shown to be related by an equation similar to eq 2.…”