ArF LASER (193 nm) PHOTOLYSIS OF HNO3. FORMATION OF EXCITED FRAGMENTS.

Article abstract of DOI:10.1002/bbpc.19840880719

HNO//3 was photolysed using an ArF (193 nm) excimer laser. Besides strong emission from OH(A**2 SIGMA ** plus ), weaker fluorescence from excited NO//2* was observed in the investigated wavelength range 130-900 nm. The OH(A) emission is generated by absorption of two laser photons while the NO//2* emission is produced by a one-photon process. The rotational and vibrational populations of the OH fragments can be explained by a simplified impulsive model with additional contributions from the change of the OH bond length and by a slight bending motion of the parent molecule. Monitoring the strong OH emission appears to be a sensitive method to detect gaseous nitric acid in air in the ppb range.