HARDNESS, CHEMICAL-POTENTIAL, AND VALENCY PROFILES OF MOLECULES UNDERINTERNAL ROTATIONS

The hardness (eta), chemical potential (mu), and molecular valency (V- M) profiles of C2H4, H(3)X-YH3 (X, Y = C, Si), B2H6, and HCP have been calculated ab initio using the 6-31G* basis set. These profiles corr espond to rotation around the C=C bond in C2H4 and the X-Y bond in H(3 )X-YH3, of the BHBH plane in B2H6, and of the H atom around the midpoi nt of the CP bond in HCP. The maximum hardness principle has been foun d to be obeyed in all cases. The eta and mu profiles are generally opp osite in nature. With the exception of B2H6, the V-M is maximum at the ground state equilibrium configuration of a molecule in all cases.