Nonradiative Rydbergharr;valence relaxation of NO trapped in Ar, Kr, and Xe matrices

摘要

Electronic and vibrational relaxation of NO in Ar, Kr and Xe matrices has been studied using excitation spectra and time and energy resolved emission spectra. In addition to the vibrationally relaxed emissions fromathinsp;4Pgr;(v=0),Bthinsp;2Pgr;(v=0) andAthinsp;2Sgr;+(v=0) in Ar and Kr matrices,B(v=5 and 7) emissions are observed in Ar matrices. In Xe matrices, only RydbergAthinsp;2Sgr;+(v=0) fluorescence is observed. Nonradiative Rydbergndash;valence transitions are observed in all matrices and valencendash;Rydberg transitions only in Ar matrices. The intensity ratiosIA/IB/Iaare sim;3/9/88 in Ar, sim;9/3/88 in Kr, and sim;2ndash;5/0/0 in Xe matrices. The quantum efficiency for total luminescence being near unity in Ar and Kr matrices. The branching ratios for intramolecular relaxation between Rydberg and valence states are described in terms of a model which combines the intramolecular Franckndash;Condon factors with the spectroscopically determined phonon Franckndash;Condon factors and solvent enhanced spinndash;orbit matrix elements. The latter increase from Ar to Xe matrices. This increase is rationalized in terms of a semiempirical model for the heavyhyphen;atom effect on spinndash;orbit mixing. Weak Rydbergndash;Rydberg relaxation by a Dgr;v=2 step in Ar and a Dgr;v=1 step in Kr is also observed and interpreted in terms of a resonant Fouml;rsterndash;Dexterhyphen;type energy transfer. Finally in Xenon matrices, a strongly nonresonant energy transfer from then=l exciton of solid xenon to theA(v=0) Rydberg level is observed.