Molecular Fluorescence Spectroscopy of Phosphorus Monoxide in Flames Studied by a SIT-OMA System.

摘要

Molecular fluorescence of PO produced in flames and excited by an EIMAC xenon arc continuum source has been investigated. An SIT image detector combined with an optical multichannel analyzer (OMA) was used as the detector. Molecular fluorescence of PO could be observed near 246 nm in the air-acetylene, air-hydrogen, oxygen/argon-hydrogen, and the corresponding argon-separated flames, while PO fluorescence enhanced by molecular emission was observed in the nitrous oxide-acetylene flame and in the argon-separated nitrous oxide-acetylene flame. The fluorescence spectrum of PO near 246 nm is identical to the emission and absorption spectra of PO and is ascribed to the gamma system, which is caused by an electronic transition. The fluorescence intensity of PO depends primarily upon the flame temperature, and so the quenching effect of nitrogen on the fluorescence intensity could not be observed. The best detection limit for phosphorus was obtained in the argon separated air-hydrogen flame, which generated the least amount of flame background noise.