OPTICAL DETECTION OF LASER INDUCED IONIZATION IN THE INDUCTIVELY COUPLED PLASMA FOR THE STUDY OF ION ELECTRON RECOMBINATION AND IONIZATION EQUILIBRIUM
The recombination kinetics between the strontium ion and the elections have been studied in an inductively coupled plasma. Two excimer lasers have been used to pump two dye lasers which were made spatially and temporally coincident in the plasma region investigated. With the first laser system the strontium atoms were photoionized and the second laser was then used to probe the ions formed by measuring the resulting ionic fluorescence. Since the second laser was delayed (by external triggering) with respect to the ionizing laser, the temporal fate of the ions could be continuously monitored. The recombination time constant was found to be 15.5 mus, indicating the absence of fast ion chemistry (in the tens of nanoseconds range) which was observed in an air- acetylene flame. Moreover, it was found that: (i) the addition of an easily ionizable element (K, Li) increased the rate of recombination; and (ii) the recombination time constant was directly proportional to the ion/atom ratio of strontium. It was concluded that changes in the number density of low energy electrons is more relevant to the rate of recombination than changes in the absolute number density of electrons.
Bibliographic Reference: 1987 WINTER CONFERENCE ON PLASMA AND LASER SPECTROCHEMISTRY, LYON (FRANCE), JAN. 12-16, 1987 SPECTROCHIMICA ACTA, VOL. 42B (1987), NO. 7, PP. 873-881
Record Number: 1989126048601 / Last updated on: 1989-01-01
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