AN APPROXIMATE ABINITIO STUDY OF THE POLARIZABILITY AND HYPERPOLARIZABILITIES OF ORGANIC-MOLECULES

We propose a simplified and approximate ab initio theory and apply it to the calculation of the electrical susceptibilities of benzene and polyenes of various sizes. The results are compared with those obtained by semi-empirical techniques as well as conventional ab initio formalisms. The main purpose here is to introduce an alternative approach to the calculation of such properties for large molecular systems, for which the strict ab initio route is too expensive and the semi-empirical approach is not deemed accurate enough.