Abstract:The two-photon LIDFS of NO excited with 452.4 nm output of an optical parameter generator and optical parameter amplifier pumped by a Nd:YAG laser was obtained. The vibration frequency and the inharmonic coefficients of the ground electronic state of NO were calculated from the results of the spectral ascription. They are ω″e=(1 904.7±7.3) cm-1,ω″eχ″e=(14.2±1.2) cm-1, and ω″ey″e=-(0.021 8±0.009 1) cm-1 respectively. It was found for the first time that the intensity of the spectral lines departs from the Frank-Condon principle due to the self-absorption of NO molecules. The spectral line of A 2Σ(v′=0)→X 2Π(v″=0) transition disappears in the fluorescence spectra. But it appears gradually with decreasing the sample pressure and the distance from the laser-gas interaction volume to the receiving window. All of these provide an important reference for monitoring NO by the technique of laser-induced fluorescence.
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