Abstract: MATH/CHEM/COMP 2002, Dubrovnik,
June 2429, 2002

On Characterization of Molecular complexity^{} Milan Randic^{1} and Dejan Plavsic^{2} ^{1}Department
of Mathematics and Computer Science, Drake University, Des Moines, Iowa
50311, USA ^{2}Rudjer Boskovic Institute, POB 180, HR10002 Zagreb, Croatia We put forward a novel index of molecular complexity, x, taking into account the symmetry of a molecular graph and the specificity of structural components considered. The x index is defined as the sum of augmented valences of all mutually nonequivalent vertices in a molecular graph. The augmented valence of a vertex in a graph is the sum of its valence and valences of all neighboring vertices with the weight 1/2^{d} depending on their distance, d, from the vertex. The x index is examined on the set of octane isomers and some special classes of graphs. It is also compared with a certain number of alternative complexity measures considered in the literature. 