EMISSION AND ABSORPTION MEASUREMENTS ON A STRONGLY SELF-ABSORBED ARGON ATOM LINE

Spectroscopic measurements of the 7635·10 ArI line were made on an argon plasma generated in a free burning arc. The emission profile, corrected for self-absorption, was measured over a temperature range of 10 000°K to 22 000°K at 1 atm pressure. Self-absorption had a strong effect on the measured transition probability but little effect on the temperature profile that was obtained using the Fowler-Milne technique. Kirchhoff's law was used to demonstrate local thermodynamic equilibrium. An iterative technique that corrected line profiles using Kirchhoff's law yielded results that agreed with the measured line profiles. The transition probability measured in this study is 2 1 2 times greater than that reported in a shock tube experiment. Using the measured absorption coefficients, corrections were applied to the shock tube measurement giving a transtition probability that agrees with the one reported in this study. © 1969.