Dipole moments and conformation energies for substituted ethanes

By using simple model potential energy functions for internal rotation of ethane derivatives (CH2X–CH2X and CHX2–CHX2), a comparison was made between the continuum and the rotational isomeric state models for obtaining conformation information (especially energy differences for the staggered conformers) from electric dipole moments. It is found that the results obtained by the two procedures may be appreciably different, depending on the features of the conformational energy function and on the temperature considered.