Interaction of NO(A2Sigma+) with rare gas atoms: potential energy surfaces and spectroscopy.

We present the results of an ab initio study of the interaction of electronically excited NO(A (2)Sigma(+)) with rare gas (Rg) atoms. The bound states of each NO(A)-Rg species are determined from potential energy surfaces calculated at the RCCSD(T) level of theory. Making use of the NO(X (2)Pi)-Rg vibrational wavefunctions, we then simulate electronic spectra. For NO-Kr and NO-Xe we obtain good qualitative agreement with the previously published experimental spectra. For NO-Ar, the shallowness of the surface gives rise to agreement that is less satisfactory, but a global scaling provides better qualitative agreement. The assignment of the spectra is far from straightforward and is only possible with guidance from the calculated energies and wavefunctions of the energy levels of the complex. Previous assignments are discussed in the light of this conclusion.