Distributions of intensities of line and continuous spectra emitted from a plasma jet flame are investi-gated along the flame axis, and the following are found.
(1) The temperature dependence of the intensity of FeI 3719.9Å line is larger than that expected by assuming the local thermal equillibrium.This is because the excitation of atom does not conform to the Boltzman distribution law.
(2) By comparison of the recombination coefficient between electron and argon ion with the decay rate of continuous spectra, together with the “apparent” temperature dependence of the intensity of continuous spectra, it is concluded that the electron density in the plasma jet flame is not governed by the equilibrium condition but by the recombination rate.
When the spectroscopic analysis is carried out by means of photographic photometry, the ratio of the intensities between the line and continuous spectra becomes an important factor which determines the analytical sensitivity.From the study of this ratio, followings are found.
(1) When a plasma is cooled, the ratio increases more than ten times in the case of atomic lines.
(2) When a plasma is cooled by spouting itself into air, N2-band appears in the spectra, and as the results the value of the ratio fluctuates.It is therefore better to use a cooling device.
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