Detection of fluorescence from O and N atoms induced by two-photon absorption.

The 3p (3)P state of O and the 2s(2)2p(2)3p (4)D(0) states of N are populated by two-photon absorption at 226 and 211 nm, respectively, and the resulting near-IR fluorescence is detected. The exciting photons are provided by stimulated Raman frequency shifting, and the experiments are performed in a flow discharge. The measured lifetime of 39 (0) and 27 (N) nsec and quenching rate constants of 2.5 x 10(-10) cm(-3) sec(-1) for collisions of N(2) with each atom indicate promise for this method as a diagnostic tool in flames and plasmas.