On the Lifetime of the MetastableP23Neon Atom

To measure the lifetime of the metastable ${}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}$ neon atom, the light from a Plücker tube was passed through the absorption tube which contained neon gas at various pressures ranging between 5.2 and 0.25 mm Hg. The gas was excited by external electrodes connected to the secondary coil of a high-frequency oscillator. By adopting the method of the rotating disk the percentage of absorption of the line ${}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}-{}_{}{}^3{}_{}{}^{}D_3^{}{}_{}{}^{}$ at various stages after the interruption of the excitation of the gas in the absorption tube, was measured. The result obtained was that the life of the ${}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}$ neon atom at a pressure of 5.2 mm Hg is about 0.005 sec., which is very near that already reported by Dorgelo, but several times longer than that obtained by Meissner and Graffunder. The effects of impurity and of temperature were also investigated.