Photoionisation calculations for the s subshells of atomic sodium

On the application of relaxed-orbital and sudden perturbation approximations for the photoionization of atoms

“…To demonstrate strong dependence of the P ( λ|r) on the final term the cross sections calculated using the solutions of HF equations in the average of the configuration approximation are also included in figure 5. They coincide with the cross sections presented by Craig and Larkins (1985a) . The cross sections of the transition 2p 6 3s 2 S → 2p 5 3s( 1 P) s 2 P in Na calculated satisfying the orthogonality of P ( s|r) and P (3s|r) from 2p 5 3s 2 2 P (solid curve: length form; dotted curve: velocity form) and without using orthogonality (dashed curve: length form; dasheddotted curve: velocity form).…”

“…The β of the R-matrix method is very close to that of SP only near the ionization threshold and the parameter β becomes lower for both ROHF and SP for high photon energies. The averaged values of β calculated using the ROHF approximation by Craig and Larkins (1985a) coincide with those of the ROHF of this paper. In the interval between 65 and 70 eV, the values of β are not displayed in figure 12 because of the difficulties of reproducing the crowded resonances displayed in the figure of Cubaynes et al (1998).…”

“…For photon energies larger than 90 eV, the β of ROHF is slightly lower than that of SP. The values of β averaged using calculations in the ROHF approximation for final terms 1 P and 3 P by Craig and Larkins (1985a) are very close to those of the ROHF approximation of this paper. At the threshold small differences between the values of β of the present calculation and that by Craig and Larkins (1985a) can be caused by the addditional orthogonality constraint imposed by us on the P ( s|r) of the final state 2p 5 3s 1 P. Parameters β of the R-matrix method are lower than those of the ROHF and SP approximations for low photon energies, but merge with the β of ROHF when the photon energy exceeds 100 eV.…”

“…However, this did not result in noticeably improved agreement with experimental data. The importance of relaxation effects has been demonstrated by Craig and Larkins (1985a, b) in the calculations of 2p and 2s photoionization cross sections of Na atoms using the ROHF approximation. The 2p photoionization cross sections were found to be 0.8 times smaller than those of the unrelaxed HF approximation by Theodosiou and Fielder (1982).…”

Fundamental Aspects of Atomic Photoionization with High-Brightness Light Sources

“…Thus, relaxation is more significant for the 3p initial state, leading to the enhanced satellite intensity, in agreement with theoretical predictions. [66] Clearly, by these arguments, this relaxation effect will be even more pronounced for more highly excited states. A recent calculation [67] investigated inner-shell photoionization for excited states of lithium.…”