POSITION INVARIANT INDEX FOR ASSESSMENT OF MOLECULAR SIMILARITY

In this study the idea of the topological similarity index has been ge neralized so that its applicability reaches beyond a simple HMO model to semi-empirical or even ab initio methods. The greatest advantage of this new index is its complete positional invariance, which makes it possible to avoid time consuming optimization with respect to the mutu al position of molecules. As a consequence of this invariance, the ind ex can find a number of interesting applications, especially in the de sign of compounds with desired biological properties. The applicabilit y of the index has been numerically tested on a series of isosteric an d isoelectronic molecules.