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

The 3p 3P state of O and the 2s 22p 23p 4D0 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 (O) and 27 (N) nsec and quenching rate constants of 2.5 x 10-10 cm-3 sec-1 for collisions of N2 with each atom indicate promise for this method as a diagnostic tool in flames and plasmas