Many new transitions from the (3sσ) A2Σ+ state to higher Rydberg and valence states in 14N16O have been observed by the technique of optical-optical double resonance-multiphoton ionization. Upper states include members from the np, nd, nf Rydberg states (n = 3 to 6) and several vibrational levels of the B2Π and L2Π valence states. The spectral simplification aspect of the double resonance technique allows for the observation of these spectra without appreciable band overlap. Analysis of our data leads to the identification of several previously unobserved mixed Rydberg-valence vibrational levels. Discussions of the Rydberg-valence interactions in the 68600-71200-cm-1 energy region of 14N16O are presented in light of these results. © 1986 American Chemical Society.