Resonance broadening in neon at low densities

The spectral profile of the strongly resonance-broadened transition lambda 585.2 nm of Ne I has been studied in absorption. A narrow-band tunable dye laser probed a weak discharge in natural neon cooled with liquid nitrogen. The Lorentzian width extrapolated to zero density was found to be 108+or-20 MHz, consistent with the value 114+or-4 MHz calculated from the natural widths of the levels. There is no indication of the excess width found in earlier emission experiments in helium and neon. A preliminary result of (1.7+or-0.2)10 -21 MHz atom -1 m 3 was obtained for the broadening constant of lambda 585.2 nm in absorption at 77K. This is consistent with the value found in emission.