Electronic spectroscopy of the 3d Rydberg states of NO-Rg (Rg = Ne, Ar, Kr, Xe) van der waals complexes

We have employed (2+1) resonance-enhanced multiphoton ionization spectroscopy to record electronic absorption spectra of NO-Rg (Rg=Ne,Ar,Kr) van der Waals complexes. The nitric oxide molecule is the chromophore, and the excitation corresponds to an electron being promoted from the 2p pi* orbital to 3d sigma, 3d pi, and 3d delta Rydberg states. We review the ordering of the 3d lambda states of NO and use this as a basis for discussing the 3d components in the NO-Rg complexes, in terms of the interactions between the Rydberg electron, the core, and the Rg atom. Predissociation of the (H) over tilde' (2)Pi state occurs through the (F) over tilde (2)Delta state for NO-Ar and NO-Kr, and this will be considered. We shall also outline problems encountered when trying to record similar spectra for NO-Xe, related to the presence of atomic Xe resonances. (c) 2006 American Institute of Physics.