SPECTRAL STUDY OF NO2 FLUORESCENCE EXCITED BY 11 LINES OF ARGON AND KRYPTON ION LASERS

High-resolution spectra of the fluorescence of NO2, excited by 11 Ar+ and Kr+ laser lines between 4579 and 5208 Å, have been obtained at NO2 pressures from 10-310 torr. Rotational lines as well as vibrational bands are observed superimposed on a continuum extending from the exciting line to the observation limit of 7500 Å. Vibrational assignments of the fluorescent bands have been made, and vibrational constants of the gound electronic state have been determined. The pressure dependence of absorption coefficients of NO2 at the laser wavelengths also was measured; an excited-state lifetime near 10-5 sec was estimated from these absorption coefficients. In addition, the lifetime of excited NO2 was measured to be 5times;1016 sec from the observation of the increase in visual size of the fluorescence beam at low pressure. Preliminary values of στV (square of collision diameter times lifetime) of the fluorescence excited by the 4880-̊ line were measured to be approximately 7×10-20 cm2.sec for line emission and 0.5×10-20cm2.sec for the integrated continuum emission, respectively; this difference is attributed to the difference in rates of rotation-vibration collisional transfer and electronic quenching.