Molecular electronic excitations and the minimum polarizability principle

The validity of the minimum polarizability principle upon electronic excita tion is studied as a companion principle of that obtained by Chattaraj and Poddar in the case of the maximum hardness principle. Twelve diatomic molec ules have been selected and, both the hardness and the dipole polarizabilit y for the ground and excited states have been calculated by means of ab ini tio density functional calculations using Sadlej's basis set. It has been f ound that a molecule is less polarizable in its ground state than in an ele ctronically excited state of the same spin multiplicity.