Centric connectivity index by shell matrices

Relative centricity rc values of vertices/atoms are calculated within the distance detour and cluj-distance criteria on their corresponding shell transforms. the vertex rc distribution in a molecular graph gives atom equivalence classes, useful in interpretation of nmr spectra. timed by vertex valences, rc provides a new index, called centric connectivity cc, which can be useful in the topological characterization of graphs and in qsar/qspr studies.