Laser spectroscopic measurements of fine structure changing cross sections of alkali earth ions in collisions with molecular hydrogen (H2, D2)

Abstract

Production of alkali earth ions (Ca+, Sr+ and Ba+) by means of a laser ablation technique and measurement of their laser-induced fluorescence, cross sections of collision-induced transitions between the np 2PJ fine structure levels (n= 4, 5 and 6 for Ca+, Sr+ and Ba+, respectively) due to collisions with hydrogen molecules at room temperature (298 K) has been performed. The cross sections thus determined for the collisions with H2 and D2 are σ(Ca+: 4p 2P3/2 → 4p 2P1/2) = 20.5 ± 0.5, 27.1 ± 1.3 Å2, σ(Ca+: 4p 2P1/2→ 4p 2P3/2) = 13.2 ± 0.6, 18.7 ± 0.8 Å2, σ(Sr+: 5p 2P3/2→ 5p 2P1/2) = 22.7 ± 0.4, 18.0 ± 0.4 Å2 and σ(Ba+: 6p 2P3/2→ 6p 2P1/2) = 10.4 ± 0.1, 3.4 ± 0.2 Å2, respectively.