Substituted Methanes. XX. Potential Constants and Calculated Thermodynamic Properties for Some Dibromomethanes

Abstract

Using previous infrared and Raman data, a reasonable set of potential constants were obtained for CH2Br2 and CD2Br2, by means of the Wilson FG matrix method, with a potential energy function containing all possible second degree terms. Fundamental frequencies for CHDBr2 were then calculated using the potential constants found for CH2Br2 and CD2Br2. Finally the heat content, free energy,entropy, and heat capacity for the ideal gaseous state at 1 atmos pressure were calculated for these three molecules for twelve temperatures from 100°K to 1000°K with a rigid rotator harmonic oscillator approximation.