Absolute hardness of ground and hybridised states of atoms

Abstract

First calculations of the absolute hardness parameter eta are reported for a large number of atoms in the ground electronic state using the relativistic local density functional which includes the effects due to electron correlation. The results are found to be in excellent agreement with experimental values and are more reliable than the non-relativistic estimates available in the literature. In the cases of B, C, N, Al, Si and P atoms, empirical estimates of eta corresponding to the hybridised sp, sp² and sp³ states are found to differ significantly from the ground-state eta values.