Measurements of Oscillator Strengths for the Transitions from the Metastable 3P Levels of Alkaline-Earth Atoms. III. Calcium–Low-n Members

Abstract

Oscillator strengths ( f values) for the transitions 4 s 4 p 3 P –4 s n d 3 D with n =6 to 12 and -3 d 5 s 3 D of Ca have been determined relative to those of the multiplet 4 s 4 p 3 P –4 p 2 3 P by means of the hook method. The resulting f values are 12–35% smaller for n =6, 7 and 8 than the data of NBS compilation by Wiese et al. Those for other members are first reported in this paper. The spectral density of the f values is found to have a minimum value around 3 d 5 s 3 D and 4 s 9 d 3 D . This behavior is quantitatively explained by means of a multichannel quantum defect theory.