We have measured the spectral distribution, intensity, and excitation temperature of pulsed discharges in sodium and thallium iodide vapors with mercury or argon. Peak plasma temperatures are in the neighborhood of 10 000°K. Both peak intensity and peak plasma temperature increase less than linearly as functions of energy input at energies over 5 J/cm3 of arc tube volume. In comparison with continuous operation, both the mercury spectrum and a continuum are enhanced relative to the iodide spectrum in pulsed NaI–Hg and TlI–Hg arcs, and the Na or Tl and Hg lines become strongly broadened. The radiant output of Na or Tl in iodide–argon pulsed arcs is limited by lack of significant line broadening.
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