Ion Enhancement by Dual-Laser Ionization in an Acetylene/Air Flame

Abstract

A technique of dual-laser ionization (DLI) is employed to detect Na trace released in an acetylene/air flame. In comparison with laser-enhanced ionization (LEI), a measurement of ion enhancement by the DLI method is found to be as large as two orders of magnitude. The ratio of DLI/LEI depends upon various factors, such as the second-step transition probability, the laser intensity, the transition linewidth, and the collisional ionization rate involved in the LEI mechanism. However, the relative ion enhancement with respect to the various second-step excitations is largely dominated by the ratio of the corresponding second-step transition probability. On the basis of this factor, a comparison between observation and estimation is found to be in satisfactory agreement.

Keywords

Dual-laser ionization Laser-enhanced ionization Ion enhancement

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