HARDNESS AND CHEMICAL-POTENTIAL PROFILES FOR SOME OPEN-SHELL HAB-]-HBA TYPE REACTIONS - AB-INITIO AND DENSITY-FUNCTIONAL STUDY

The electronic structure, hardness (eta), and chemical potential (mu) for the (1)A' and (3)A '' states of HNO-HON and the (2)A '' State of H SO-HOS have been calculated using HF/6-311++G* and B3LYP/6-311++G** m ethods. The eta and mu profiles of the (1)A' state of HNO-HON and thos e of HSO-HOS are obtained in agreement with the salient features of th e maximum hardness principle (MHP). However, a quite erratic eta profi le is predicted for the (3)A '' State of HNO-HON. This can be attribut ed to the nature of the variation in the energy difference of the two states along the reaction path. The relative energies, ionization pote ntials (I), and electron affinities (A) are calculated at the stationa ry points of the B3LYP surface using B3LYP and MPn (Full) methods. Mos t of these values are obtained in very good agreement with the availab le experimental data. The eta values based on these I and A identify t he most stable species correctly but do not follow the expected trend with regard to the relative stability of the transition state. The rea son for this anomaly is discussed.