DIPOLE MOMENTS, HYPERFINE STRUCTURE AND LEVEL CROSSING SIGNALS IN THE LASER STARK LAMB DIP SPECTRUM OF NO

Abstract

The laser Stark Lamb dip spectrum of nitric oxide observed with the 9-8 P(13) line of the $^{12}C^{16} O$ laser at $1884.35 cm^{-1}$ consists of over fifty lines in the range from 17 to 60 kv/cm. These lines are all associated with the fine and hyperfine structure of the R.(3/2) transition in the fundamental vibration rotation band. We observe three types of lines: (1) Lamb dips which correspond to ‘real’ transitions, (2) centre dips which lie midway between ‘real’ transitions which share a common level and are due to a double resonance (“cross-over bleaching”) effect, and (3) two signals caused by level-crossings in the upper state ($^{2}\Pi_{1/2}$ component). In several instances, the centre dips are observed between a strong line and another line too weak to be observed directly. The level crossing signals make it possible to break the strong correlations between the upper and lower state dipole moments (for $^{2}\Pi^{1/2}$). Analysis of the data has thus yielded dipole moments for: v = 1/2 and v = 0 for the $^{2}\Pi_{1/2}$ component and for $v = 1$ relative to v = 0 In the $^{2}\Pi^{3/2}$ component.