01513nas a2200181   4500008004100000022001400041245005700055210005500112260008700167300001100254490000800265520088000273100002701153700002801180700001801208700001601226856008901242       2014                        eng d  a0021-960600aGround state of naphthyl cation: singlet or triplet?0 aGround state of naphthyl cation singlet or triplet  a1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USAbAMER INST PHYSICScMAR  a1143120 v1403 a<p>We present a benchmark theoretical investigation on the electronic structure and singlet- triplet(ST) gap of 1- and 2-naphthyl cations using the CCSD(T) method. Our calculations reveal that the ground states of both the naphthyl cations are singlet, contrary to the results obtained by DFT/B3LYP calculations reported in previous theoretical studies. However, the triplet states obtained in the two structural isomers of naphthyl cation are completely different. The triplet state in 1-naphthyl cation is (pi,sigma) type, whereas in 2-naphthyl cation it is (pi,sigma) type, The S-T gaps in naphthyl cations and the relative stability ordering of the singlet and the triplet states are highly sensitive to the basis set quality as well as level of correlation, and demand for inclusion of perturbative triples in the coupled-cluster ansatz. (c) 2014 AIP Publishing LLC.</p>1 aDutta, Achintya, Kumar1 aManohar, Prashant, Uday1 aVaval, Nayana1 aPal, Sourav  uhttps://library.ncl.res.in/content/ground-state-naphthyl-cation-singlet-or-triplet-0