University of Kashan Iranian Journal of Mathematical Chemistry 2228-6489 1 Issue 1 (Special Issue on the Role of PI Index in Nanotechnology) 2010 04 01 Use of Structure Codes (Counts) for Computing Topological Indices of Carbon Nanotubes: Sadhana (Sd) Index of Phenylenes and its Hexagonal Squeezes 91 94 5138 10.22052/ijmc.2010.5138 EN P. E. JOHN Technische Universitat Iimenau, Ilmenau S. AZIZ Department of Applied Sciences (Mathematics), Indore P. V. KHADIKAR Laxmi Fumigation and Pest Control, Khatipura, India. Journal Article 2014 04 20 Structural codes vis-a-vis structural counts, like polynomials of a molecular graph, are important in computing graph-theoretical descriptors which are commonly known as topological indices. These indices are most important for characterizing carbon nanotubes (CNTs). In this paper we have computed Sadhana index (Sd) for phenylenes and their hexagonal squeezes using structural codes (counts). Sadhana index is a very simple W-Sz-PItype topological index obtained by summing the number of edges on both sides of the elementary cuts of benzenoid graphs. It has the similar discriminating power as that of the Weiner (W)-, Szeged (Sz)-, and PI-indices. https://ijmc.kashanu.ac.ir/article_5138_27ded09e0fb14ea6a65bfd0082c84828.pdf