Collisional shifts and broadenings of doubly excited states of barium

Abstract

Shift and broadening parameters for doubly excited states of 5d6d, 5d7d, 5d7s, 5d8s and 6p2 configurations in neutral barium atoms are presented. A tunable dye laser pumped by an excimer laser was used to populate the Rydberg states of Ba by two-photon absorption from the 6s2 1S0 ground state. Inert gases Ar, Kr and Xe at 100 mbar pressure were used as perturbing gases. The resulting line shapes were fitted to a Voigt line shape function, from which shift and broadening parameters were inferred.

Collisional shifts and broadenings of the 4sns1S0and 4snd1D2Rydberg series of calcium perturbed by inert gases

“…For three inert gas perturbers, the nature of the graphs is the same except that the Xe perturber produces largest shifts and broadenings followed by Kr and Ar. As we showed in our previous publication on Rydberg states of Ba [12], these shift and broadening values could be verified by calculations based on electron scattering from inert gases. These calculations confirmed that the strength of interactions increased in the order of Ar, Kr and Xe.…”

“…As we reported previously, in the case of Ba these perturbations also produce anomalies in the radiative lifetimes [9], Stark effects [10], forced auto-ionization and hyperfine structures [11]. Our recent study of Ba [12] identified several anomalies for the broadening and shift values for the same states. This was part of the motivation to explore similar examples in the case of calcium.…”