@article {Ashrafi:2006:1546-1955:378,
title = "Padmakar-Ivan Index of TUC4C8(S) Nanotubes",
journal = "Journal of Computational and Theoretical Nanoscience",
parent_itemid = "infobike://asp/jctn",
publishercode ="asp",
year = "2006",
volume = "3",
number = "3",
publication date ="2006-06-01T00:00:00",
pages = "378-381",
itemtype = "ARTICLE",
issn = "1546-1955",
eissn = "1546-1963",
url = "https://www.ingentaconnect.com/content/asp/jctn/2006/00000003/00000003/art00005",
doi = "doi:10.1166/jctn.2006.007",
keyword = "PI INDEX, TUC4C8(S) NANOTUBE",
author = "Ashrafi, Ali Reza and Loghman, Amir",
abstract = "A C4C8 net is a trivalent decoration made by alternating squares C4 and octagons C8. Such a covering can be derived from square net by the leapfrog operation. Stefu and Diudea recently computed the Wiener index of such nanotubes (see Monica
Stefu and Mircea V. Diudea, MATCHCommun. Math. Comput. Chem. 50, 133 (2004).). The Padmakar-Ivan (PI) index of a graph G is defined as PI(G) = [n
eu
(e|G) + n
ev
(e|G)], where n
eu
(e|G) is the number of edges of G lying closer to u than to v, n
ev (e|G) is the number of edges of G lying closer to v than to u and summation goes over all edges of G. This topological Index is developed very
recently. In this paper, an exact expression for PI index of the TUC4C8(S) nanotubes is given.",
}