Two-photon spectroscopy of Rydberg states of NO

Abstract

Two-photon spectroscopy of supersonically cooled NO in the region between the NO+ X 1Σ+, υ+ = 0 and 1 ionization thresholds reveals the n = 7-12 members of the ndπ-, υ = 1 Rydberg series. The n = 5 member of the same series is observed below the two-photon ionization threshold by using two-photon resonant, three-photon ionization. The data are analyzed by using multichannel quantum defect theory to extract rotationless quantum defects and to reveal perturbation by the nf, υ = 1 series. Theoretical two-photon rotational line strengths are in satisfactory agreement with the observed data. © 1989 American Institute of Physics.