(A)OVER-TILDE[-(X)OVER-TILDE TRANSITION OF RG-CENTER-DOT-NO COMPLEXES(RG = RARE-GAS) OBSERVED USING RESONANCE-ENHANCED MULTIPHOTON IONIZATION (REMPI) SPECTROSCOPY - XE-CENTER-DOT-NO

The (A) over tilde <-- (X) over tilde transition of the Xe.NO molecula r complex has been studied using one-colour (1 + 1) resonance-enhanced multiphoton ionization (REMPI) spectroscopy; The spectrum shows a com plicated vibrational structure, which terminates in a sharp cut-off. T he spectrum was recorded in both the Xe.NO+ and the Xe+ mass channels; both spectra showed identical structure, except (i) the relative inte nsities of some of the features differed between the two spectra and ( ii) Xe transitions were observed in the Xe+ mass channel. The appeara nce of the Xe.NO spectrum in the Xe+ mass channel is discussed. The sp ectra allow the T-o value of the (A) over tilde <-- (X) over tilde tra nsition to be measured as 44163.2 cm(-1), as well as estimates to be m ade of the dissociation energy of both the (A) over tilde and (A) over tilde states: 121 and 157 cm(-1), respectively. The vibrational struc ture observed in the spectrum was not analysed. No (A) over tilde <-- (X) over tilde spectra of Ne.NO were observed under any of the conditi ons used. Trends in the spectroscopy and bonding of the (A) over tilde state of the Rg.NO complexes (Rg = rare gas) are discussed, and the A states of Ne.NO and He.NO are concluded to be either very weakly boun d or dissociative.