Substituted Methanes. VIII. Vibrational Spectra, Potential Constants, and Calculated Thermodynamic Properties for Dibromodichloromethane

Abstract

Raman displacements, semiquantitative relative intensities, and quantitative depolarization factors for the liquid, and infrared absorption wave numbers and percent transmission curves for both the liquid and the gas, have been obtained for CBr2Cl2. The present and previous data were critically examined and probable values of the wave numbers corresponding to the fundamental vibrational frequencies were determined. Assignments were made for all observed Raman and infrared bands. As a check on the assignments, a normal coordinate treatment was undertaken, using a potential function containing all possible quadratic interaction constants. A reasonable set of potential constants was obtained. The observed fundamentals then were used to calculate to a rigid rotator, harmonic oscillator approximation the heat content, free energy, entropy, and heat capacity for 12 temperatures from 100° to 1000°K, for the ideal gaseous state at 1-atmos pressure.