Measurements of Oscillator Strengths for the Transitions from the Metastable ³<i>P</i> Levels of Alkaline-Earth Atoms. II. Magnesium

Abstract

Oscillator strengths ( f values) for the transitions 3 s 3 p 3 P –3 s n s 3 S ( n =4 and 5), -3 s n d 3 D ( n =4 and 6 to 9) and -3 p 2 3 P in Mg I have been determined by using the hook method. The metastable 3 s 3 p 3 P levels have been populated by a DC discharge of the Mg–He mixture. The absolute scale is based on the absolute f values for 3 s 3 p 3 P –3 s 3 d 3 D (∼0.62). The determined f values are in good agreement with recent theoretical predictions. An estimate of the photoionization cross section from the 3 P levels by extrapolating the f values results in 20.2 Mb at the threshold.