Ba+(6p 2P) gas phase collisional quenching and intramultiplet mixing

Abstract

Collisional quenching and intramultiplet mixing of Ba+ (6p 2P1/2,3/2) has been studied by laser-pumping 6p 2P3/2 and measurement of the 6p 2P3/2 to 6p 2P1/2 population ratio under steady-state conditions. Gas phase Ba+ was generated by the methods of two photon ionization of Ba and by multiphoton dissociation and ionization of BaI2. The cross sections for quenching of 6p 2P1/2 by N2, CH4, C2H6, and C2H4 are 17 Å2, ≤3, ≤6, and 120 Å2, respectively. The cross sections for 6p 2P3/2→6p 6p 2P1/2 mixing by N2, CH4, C2H6, and C2H4 are 24, 70, 100, and 80 Å2, respectively. These cross sections are comparable to those of the alkali neutrals.

Laser spectroscopic measurements of fine-structure changing cross sections of Ca+and Sr+ions in collisions with He atoms

“…As for alkali earth ions, on the other hand, although their electronic configurations are identical to those of alkali metal atoms, investigations on fine-structure changing collisions of these ions have been restricted to only a few studies: producing Ba + by multiphoton ionization of gas phase Ba or BaI 2 , Hovis and Gelbwachs [7] have studied the 6p 2 P 3/2 → 6p 2 P 1/2 transition of Ba + in collisions with N 2 , CH 4 , C 2 H 6 and C 2 H 4 . Brust et al [8] have measured fine-structure changing cross sections for the 3p 2 P J state of Mg + and 4p 2 P J state of Ca + in collisions with He by means of a laser ablation technique for ion production.…”

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

“…A theoretical investigation on the resonance enhancement has been carried out by Pascale et al for the Rb-H 2 system, based on close-coupling quantum mechanical calculations [9]. On the other hand, for alkali earth ions, which have electronic structures identical to alkali metal atoms, there have been only a small number of studies on their FSC collisions [10][11][12][13][14]. Their fine structure splittings are much larger than those of alkali atoms, and are comparable to rotational energy intervals of the hydrogen molecule, which has the largest rotational constant among all molecules.…”