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The net volumetric emission coe~cient was calculated using the escape factor method for Ar/Fe and Ar/H2/Fe plasmas, at atmospheric pressure, over the temperature range from 3000 K to 30,000 K. The calculation involved 712 lines for Ar l, Ar H, and Ar lll, 3481 lines for Fe l, Fell, and Fe lll. and230 lines for H in the Ar/H2/Fe case. A semiempirical method was used for the determination of line profiles and line broadening. The results show a strong influence of the presence of even traces of iron vapors at low temperatures where the volumetric emission increases by several orders of magnitude. Special attention is given to self:absorption of the argon resonance lines which prevents the radiation from escaping within a few millimeters from the emission source.

The paper presents a theoretical study of the line and continuum radiation emitted by an argon plasma at atmospheric pressure in the presence of iron vapour a t concentrations ranging from 0.001 to 10% (molar) and temperatures up to 15000 K. The results show that the line emission is clearly the dominant mechanism due to the very rich iron spectrum. An analysis of the importance of self-absorption for the argon and iron lines indicates a strong absorption of the argon resonant lines and a significant absorption of iron lines even at low concentrations.

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