Calculated energetics of torsional motion in six diphenyl molecules: benzophenone, diphenyl ether, diphenyl sulphide, diphenyl sulphone, diphenylmethane and biphenyl

The calculation of the energetics of torsional motion in a number of aromatic, diphenyl molecules using the ab initio SCF method is described. The molecules chosen represent linkages, such as ether, ketone, sulphide, sulphone, methylene and biphenyl, which are found in many aromatic polymers. The results of the calculations should provide a useful ‘benchmark’ for attempts at using molecular mechanics methods to study the motion of the polymer chain. Where details are available, the calculated torsional and geometric parameters are in good agreement with experiment.