Preliminary ab initio study of the quartet states of the complex formed between NO(X-2 Pi) and O-2(X-3 Sigma(-)(g))

We present the results of a preliminary study of the quartet states of the complex formed between the ground-state NO ((XII)-I-2) and the ground-state O-2 (X(3)Sigma (-)(g)) molecules. Geometry optimizations are performed at the UQCISD/6-31+G* and UQCISD/6-311+G(2d) level. Binding energies are then calculated for the three lowest energy isomers at the RCCSD(T)/aug-cc-pVQZ level. The lowest energy isomer is found to be a T-shaped C-2v NO(O-2) stru cture, with a D-e value of similar to 110 cm(-1), after correction for BSSE . The favoured geometry seems to suggest that electron repulsion is an impo rtant consideration in this species. (C) 2001 Elsevier Science B.V. All rig hts reserved.