Detection and characterization of the NO(L′ 2Φi) state at 6.6 eV

Abstract

By using the techniques of stimulated emission pumping combined with fluorescence dip spectroscopy it has been possible to characterize the metastable NO(L′ 2Φ) state. The spectroscopic parameters are: Te =53 675.51 (47) cm−1, ωe =1000.0 (6) cm−1, ωexe =10.090 (64) cm−1, Be =1.1163 (39) cm−1, αe =0.016 85 (53) cm−1, Av =−42.567 (161)−0.196 (160) [v+1/2] cm−1, re =1.4222 (25) Å. The state is produced by initially populating NO(B′ 2Δ5/2, v=3, J=7.5) with 157.630 nm radiation from an F2 laser. While observing the B′–X fluorescence emission, a Raman-shifted dye laser is tuned through the appropriate spectral region (950–1300 nm), and intensity decreases are observed at the positions of the J=6.5, 7.5, and 8.5 rotational levels of the 2Φ state (as well as other states). The first four vibrational levels have been detected in this manner, with the numbering being confirmed by the recent matrix isolation detection of v=0 by Chergui et al. Perturbations in the v=1 level of the B′ 2Δ state, postulated by Huber as being due to the L′ 2Φ state, are shown to involve the v=9 level. Data for 14N16O and 14N18O at the B′(1)−L′(9) perturbations are used in the evaluation of the spectroscopic constants.