A theoretical study on the stability of N15+ cluster

Ab initio (MP2) and density functional theory (DFT) methods have been used to examine three isomers of the N-15(+) cluster with the 6-31G* basis set. The most stable isomer is the trans structure (C-S), containing one aromatic N-5 ring and two N-5 side chains. The decomposition pathways of the three isomers were studied at the B3LYP/6-31G* level of theory. Relative energies were refined at the level of B3LYP/6-311G(3df,2p) / / B3LYP/6-31G* + ZPE (B3LYP/6-31G*). The decomposition reactions of the global minimum prefer side-chain fission, with barriers of 9.3 and 12.0 kcal mol(-1) for N-2 and N-5(+) (C-2v) ssion reactions, respectively. The ring breaking reaction has a barrier of 19.4 kcal mol(-1). The corresponding side-chain ssion barriers for the second structure (C-2v), which is a cis isomer, are predicted to be 9.3 kcal mol(-1) and 12.1 kcal mol(-1), respectively. The barrier height for breaking the center ring of the three connected N5 rings of the third structure (C-2) is predicted to be 8.0 kcal mol(-1).