Absolute Raman intensities, force constants, and electro-optical parameters of CH₂Cl₂, CD₂Cl₂ and CHDCl₂

Abstract

The absolute Raman intensities and depolarization ratios of all the fundamental bands of CH₂Cl₂, CD₂Cl₂ and CHDCl₂ have been measured in the gas phase. These experimental data have been included in a refinement of the vibrational potential function of the dichloromethanes. A detailed description is made of the use of the bond polarizability approach. Explicit expressions for the derivatives of the molecular polarizability with respect to the symmetry coordinates are given in terms of the zeroth- and first-order electro-optical parameters of the theory. Good agreement is found between experimental and calculated intensities. The refined electro-optical parameters compare quite well with those obtained from methane, chloroform and carbon tetrachloride. The derivatives of the molecular polarizability with respect to the normal coordinates are also given.