Abstract: | In the present study, a number of positional and geometrical isomers have been considered to study the stability of isomers using the maximum hardness principle (MHP). All the considered isomeric molecules were optimized and the chemical hardness η and chemical potential μ 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 μ and external potential v(r), which arises due to the formation of a bond with different atoms. But, for the most of geometrical isomers, the MHP was able to predict the most stable conformer of the molecule. So, the present investigation suggests that the MHP is not applicable for the prediction of isomer stability for all the isomeric molecules. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 76: 648–655, 2000 |