A Study of the Formation of the 1.15 Micrometer Spectral Line of Neon in a DC Discharge

摘要

An investigation was conducted to study the effects of the kinetic state of an absorbing gas on the formation of its spectral lines. The spectral line profile of the 1.15 micrometer transition in Ne(22) was measured over a range of dc discharge pressures and currents using tuned laser absorption spectroscopy with He-Ne tunable laser light source oscillating at 1.15 micrometer. The measured shapes and lineshape parameters were compared with those predicted by the theories of spectral line formation. The influence of the state of the gas on its spectral line structure was then deduced from that comparison between the results of theory and experiment. The measured lineshapes were fitted with both Voigt profiles and Rautian-Sobel'man profiles (strong-collision model). The latter profiles account for the effects of velocity-changing collisions, which can produce narrowed lineshapes. Under certain conditions, collisional line narrowing was observed; this was inferred from the fits of Rautian-Sobel'man profiles, which fit the measured lineshapes when Voigt profiles did not. (Author)