Nitrogen dioxide fluorescence following photolysis in a supersonic jet.

摘要

A supersonic jet of N(sub 2)O(sub 4) has been photolyzed at three wavelengths: 193, 248 and 351 nm. The resultant fluorescence of NO(sub 2) was dispersed, and from this the energy distribution of fluorescent NO(sub 2) has been determined by the Photolysis Induced Fluorescence (PIF) scheme. The spread of the energy distribution increased with decreasing photolysis wavelength. The photolysis of NO(sub 2)Cl at 248 nm resulting in NO(sub 2) fluorescence was analyzed by the PIF (Photolysis Induced Fluorescence) deconvolution scheme and these results were compared to and Time-of-Flight/Mass Spectrometry (TOF/MS) performed previously in Y.T. Lee's lab by Oh and Coworkers. The results from the pulsed beam PIF agreed with the TOF/MS results leading to 5 product channels in NO(sub 2)Cl photolysis. The undispersed fluorescence of NO(sub 2) is observed following the excitation of NO(sub 2)Cl, N(sub 2)O(sub 4), and NO(sub 2). The Photolysis Induced Fluorescence Excitation (PIFEX) spectrum of NO(sub 2)Cl shows a decrease in the fluorescence quantum yield, (phi)(sub f), when scanning to shorter wavelength. This decrease in (phi)(sub f) is attributed to the onset of the NO + O + Cl channel. The NO(sub 2) LIF spectra yield information on 3 parallel bands observed near 400 nm as well as a confirmation on D(sub 0), which is found here to be 3978.3 (plus minus) 0.03 (angstrom) (air-calibrated).