Oscillator strength measurements of the 3p(5)((2)P(1/2)) nd '[3/2](2) and [5/2](2,3) autoionizing resonances in argon

摘要

We present measurements of oscillator strengths of the 3p(5)nd' J = 2,3 autoionizing Rydberg states in argon using two-step laser excitation in conjunction with an optogalvanic detection in a dc discharge cell. The 3p(5)4p'[3/2](1,2) and [1/2](1) intermediate levels were populated via the 3p(5)4s[3/2](2) metastable state, collisionally populated in the discharge. The photoionization cross section from the 3p(5)4p'[3/2](1,2) and [1/2](1) intermediate levels has been measured at the 3p(5) (2)P1/2 ionization threshold as 34 +/- 5, 31 +/- 5, and 28 +/- 4 Mb, respectively, using the saturation technique. The measured absolute cross section values at the 3p(5) (2)P(1/2) threshold have been used to determine the f values for the 4p'[3/2](1) -> nd'[5/2](2), 4p'[3/2](2) -> nd' [5/2](3), and 4p'[1/2](1) -> nd'[3/2](2) transitions. The extracted f values are corrected by incorporating the contribution of the Fano line shape parameters for the autoionizing resonances.