Possibility of Measuring a Quadrupole Transition Probability from an Auroral Afterglow

Abstract

THE green auroral line of oxygen at 5,577 A. (¹D₂ – ¹D₀) has been found by Vegard and Kvifte¹, and Jenkins, Bowtell and Strong² in the afterglow of a Tesla discharge through argon, or a mixture of argon and nitrogen, at nearly atmospheric pressure, when there is a minute trace of oxygen present. It is accompanied by a diffuse band similar to one described by L. and R. Herman³. We have made some measurements of the decay of this phosphorescence, which can be followed by a photo-multiplier connected through an amplifier to a cathode ray oscillograph with a low-frequency time base. Three sources have been used, namely, two 300-watt commercial Osram gas-filled lamps, and a cylindrical tube 21 cm. long and 6 cm. in diameter containing a similar gas mixture, with two rod electrodes 2 mm. in diameter, mounted near one end with their tips 3 cm. apart. The photomultiplier was exposed to the glow from a volume of gas about 3 cm. in linear dimensions.