The Vertex-Connectivity Index Revisited

We report a search for optimum molecular descriptors based on the connectivity index. A suggestion made by several authors that the exponent −0.5 used in the standard formula for computing the connectivity index may not be the optimum for modeling some molecular properties was reexamined. We considered several molecular properties and found that in most cases the optimum value of the exponent is indeed different from −0.5. We suggest that a modified version of the (valence) vertex-connectivity index should be routinely employed in the structure−property modeling instead of the standard version of the index.