We investigate the (A) over tilde (2)Sigma(+) state of NO-Ne by high-level ab initio methods, and by (1 + 1) resonance-enhanced multiphoton ionization spectroscopy (REMPI). Despite being able to obtain high-quality spectra of NO-Ar, NO-Kr and NO-Xe, no spectrum of NO-Ne was observed. It is shown that this state is very weakly bound; and that the overlap between the zero-point vibrational energy level in the (X) over tilde (2)Pi state, and the bound levels of the (A) over tilde (2)Sigma(+) state is very small: hence the Franck-Condon factors are close to zero. The location of the Ne atom outside the 3s Rydberg orbital is the cause of the observations. (c) 2007 Elsevier B.V. All rights reserved.