Absolute measurement of the photoionization cross section for ground-state cesium atoms

Experimental and theoretical cross sections for photoionization of metastable Xe*. (6s 3 P 2, 3 P 0) atoms near threshold

“…As already mentioned above in connection with Fig. 2 process (3) possesses the largest cross section by far while the cross section for the alkali-like process (4) in which only p-waves are emitted has small values around 0.05 Mb; they are close to the cross sections for Cs(6s) photoionization at the same photoelectron energies [32] (see Sect.…”

“…Several calculations of this process have been reported within nonrelativistic [25,26] and relativistic [26][27][28][29][30][31] approximations, with inclusion of many electron correlations [25,30,31] and without [26,27,29]. The energy dependence of the cross section σ 6s [32,33] and the angular distribution parameter β 6s [34] for 6s photoionization have been carefully studied experimentally and exhibit interesting variations over the photoelectron energy range 0-2 eV which present sensitive tests of the theoretical calculations. Below we compare our theoretical results with previous work [25][26][27][28][29][30][31][32][33][34].…”

“…In particular, they were also applied for the calculation of σ and β of the metastable states. [30], c calculation within the Dirac-Fock approximation [29], d Breit Pauli Hartree Fock calculation with relaxed core [26], open circles: experimental results taken from [32] (σ) and [34] (β) The photon energy ω and photoelectron energy ε are connected by the equation ω = IP(6s) + ε where IP(6s) represents the ionization energy of the 6s electron in Cs. The theoretical value IP T h (6s), calculated in the present work, consists of two parts: single particle IP P F (6s) and correlational IP CR (6s).…”

“…The energy dependence of the cross section σ 6s [32,33] and the angular distribution parameter β 6s [34] for 6s photoionization have been carefully studied experimentally and exhibit interesting variations over the photoelectron energy range 0-2 eV which present sensitive tests of the theoretical calculations. Below we compare our theoretical results with previous work [25][26][27][28][29][30][31][32][33][34].…”

“…3 we present the Pauli-Fock approach, used to take into account relativistic effects, and the configuration interaction method to account for electron correlation effects. Moreover, we test these techniques by photoionization calculations for Cs(6s) and comparison with previous theoretical [25][26][27][28][29][30][31] and experimental [32][33][34] work. In Sect.…”