[Laser induced dispersed fluorescence spectra of NO2 in the range of 550-740 nm].

Laser induced dispersed fluorescence spectra (LIDFS) of NO2 molecules, excited by second harmonic lines (the output wavelength is 532 nm) of a pulsed Nd: YAG laser at room temperature and at low and high NO2 pressures, were obtained and analyzed. The authors got vibronic progressions in the range of 550-740 nm at low pressure and ascribed them to the transitions from the first excitation electronic state A(2)B2 to the vibrational levels of the ground electronic state X(2)A1, and then calculated the harmonic frequencies of symmetry stretch and bond stretch: omega1 = 1300.72 cm(-1) and omega2 = 744.14 cm(-1), respectively. On the basis of what was above-mentioned, the authors compared the spectra at low pressure with those at high pressure and pointed out the difference between them. Then the authors also interpreted the obvious red shift of fluorescence spectra at high NO2 pressures in terms of a stepladder model of vibrational deactivation and obtained significative results.