New time and energy resolved data on vibrationally relaxed and unrelaxed emissions from the valence a4P(v = 0), B2P(v = 0,3,4,5), and the Rydberg A2S+ (v = 0,1,2) states of NO in Ne matrixes are reported. Rydberg .tautm. valence and valence .tautm. valence nonradiative transitions were identified. The Rydberg -> valence transitions occur after lattice relaxation accommodating the Rydberg orbital. The branching ratios for intramol. relaxation and the measured lifetimes are described in terms of a model which combines the intramol. spin-orbit matrix elements and Franck-Condon factors with the spectroscopically detd. phonon Franck-Condon factors. For the levels B2P(v = 5,6), a Foerster-Dexter-type energy transfer between NO mols. is invoked in the description of the relaxation cascade. [on SciFinder (R)]