Studies of isomer stability using the maximum hardness principle (MHP)

In the present study, a number of positional and geometrical isomers have b een considered to study the stability of isomers using the maximum hardness principle (MHP). All the considered isomeric molecules were optimized and the chemical hardness eta and chemical potential mu were calculated at the HF/6-31G level of theory. The MHP was not able to predict the stability of the most of the positional isomeric molecules, because of the variation in the chemical potential mu and external potential v(r), which arises due to the formation of a bond with different atoms. But, for the most of geometri cal isomers, the MHP was able to predict the most stable conformer of the m olecule. So, the present investigation suggests that the MHP is not applica ble for the prediction of isomer stability for all the isomeric molecules. (C) 2000 John Wiley & Sons, Inc.