Measurement of pressure shift and broadening coefficients for Ne 3s[3/2]2 → 3p[5/2]3 transition in Ne and He using diode-laser absorption spectroscopy

Measurements of pressure broadening and shift coefficients for 640.2 nm Ne line were performed in an RF discharge without stabilization of neutral gas temperature. A diode laser with a short external cavity was used for metastable neon absorption spectroscopy in a natural mixture of neon isotopes. An appropriate fit function was constructed permitting deduction of Doppler and Lorentz components for the Voigt profile of the spectral line. To determine pressure broadening xi and shift beta coefficients for pure Ne and Ne:He mixture we used the information about Lorentz linewidth, position of the line center and gas temperature derived from spectral line shape fitted to a model line profile. The values of the collisional coefficients reduced to 300 K in units of 10(-10) s(-1) cm(3), are xi(Ne-Ne )= (1.9 +/- 0.2), xi(Ne-He) = (3.4 +/- 0.2); beta(Ne-Ne) = -(0.7 +/- 0.1), beta(Ne-He) = (0.13 +/- 0.04). (C) 2020 Elsevier Ltd. All rights reserved.