Doppler-limited dye laser excitation spectroscopy of DNO: Predissociation of DNO

The cw dye laser excitation spectrum of the (110)-(000) and (021)-(000) vibronic bands of the system of DNO was observed between 16530 and 16860 cm⁻¹ with Doppler-limited resolution. A rotational analysis of the two bands gave values for the rotational constants and centrifugal distortion constants. DNO was produced by the pyrolysis method and more than 1200 lines were observed in the two bands. A total of 1112 of these lines could be assigned to 9 and 11 subbands of the (110)-(000) and (021)-(000) bands, respectively. The molecular constants determined reproduce the observed transition frequencies with an average deviation of 0.011 and 0.008 cm⁻¹, respectively. Extensive perturbations in the excited state were found in most of the subbands. “Extra” lines were observed in connection with several of these perturbations. Accurate determination of the dissociation energy has been obtained; D₀ = 17010 ± 10 cm⁻¹.