Preliminary ab initio study of the quartet states of the complex formed between NO(X 2?) and O2(X 3?g?)

We present the results of a preliminary study of the quartet states of the complex formed between the ground-state NO(X 2?) and the ground-state O2(X 3?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 C2v NO(O2) structure, with a De value of 110 cm?1, after correction for BSSE. The favoured geometry seems to suggest that electron repulsion is an important consideration in this species