Knowledge Bank

The one-colour REMPI spectrum of Ar$\cdot$NO and Kr$\cdot$NO have been recorded where the resonances are occurring in the $A~2\Sigma +$ (3s) Rydberg state, which is localised on the NO moiety. Structure is seen which initially suggests assignment to intermolecular vibrational modes; however, in fact it appears that this structure is associated with rotation of the whole complex, essentially about the intermolecular axis. Rotation of the complex about the other rotational axes is not resolved in this work, but causes broadening of the observed lines.