Topological Indices Based on Line Graph of Different Chemical and Non-Chemical Structures

Abstract

Chemical compounds have variety of physicochemical, toxicological and pharmaco- logical properties which predict their nature and how they will react. But the study of these properties requires Herculean and laborious experimentation so its alternative, topological indices were invented about 150 years ago which is the greatest break- through in the field of mathematical chemistry. It provides the substitute to scrutinize the behavior of chemical graphs and an easy approach for substantiating their existing numerous properties and thus helps in designing novel drugs and compounds. This was achieved due to the birth of chemical graph theory in which modeling of chemical compounds can be done. In this research, miscellaneous mathematical and computational techniques are applied for the calculation of several degree-based and spectrum-based topological invariants for boric acid (H3BO3) layer structure’s derivatives (subdivision, line graph and caged chain). The molecular descriptors being computed are the harmonic index; two ver- sions of Randic´, sum-connectivity, atom-bond connectivity, geometric-arithmetic and Zagreb indices. Besides these, the list also includes Estrada index, energy and the distance energy of above-named graphs. Pre-invented formulae are used for their cal- culation and for spectrum-based invariants, polynomials are generated and vindicated based on results.