The Dipole Moments of Molecules Containing Two Movable Dipoles

Abstract

The average dipole moment of a molecule containing two movable dipoles has been calculated as a function of temperature and restriction to internal rotation for three different potential functions. The potential functions used are: (V₀/2)(cos φ+1), (V₀/π)(π—φ) and V₀/π²(π—φ)², where V₀ is the difference in potential energy between the cis and trans forms of the molecule and φ is the angle between the planes containing the dipoles and the axis of rotation. Values of the integral ${\displaystyle {\int }_0^{\pi }}\cos \mathrm{x\hspace{0.17em}}\exp {\mathrm{(-bx}}^2\mathrm{)dx}$ are tabulated for values of b ranging from 0 to 2 at intervals of 0.1. The dipole moments of s‐dichloro‐ethane, 1,2‐bromo‐chloro‐ethane and s‐dibromo‐ethane as a function of temperature are used with the three potential functions to determine values of V₀. The values thus obtained are compared with the values obtained by other methods.