Subshell photoionization cross

D.A. Vemer, D.G. Yakolev, I.M. Band, M.B. Trzhaskovskaya, Subshell photoionization cross sections and ionization energies of atoms and ions from He to Zn, At. Data Nucl. Data Tabl. 55 (1993)233. 

Schofield, J. H. (1976). Hartree-Fock subshell photoionization cross-sections at 1254 and 1487 eV. J. Electron Spectrosc. Relat. Phenom. 8, 129-37. 

Table 6.6 Theoretical atomic subshell photoionization cross-sections for MoVTeNb-related valence band orbitals at different photon energies, according to the calculations ofYeh and Lindau [177].

The theoretical calculation for peak intensity of photoelectron spectram has been carried out in the framework of DV-Xa method. First we ealculate the atomic subshell photoionization cross sections. The photoionization cross section for atomic orbital... 

Fig. 6. Ba 4d"Hkf subshell photoionization cross sections calculated by Wendin, ref. 58. Expt. by Rabe et al., ref. 58a, normalized to contain 10 electrons.

A compilation of subshell photoionization cross sections for the six elements at Al Ka radiation energy (1486.6 eV) scaled to of Na (0.118Mb), derived from photoelectron spectrometry, can be found in [11]. See also [12, 13]. 

The dependence of confinement resonances on quantum numbers of the ionized subshell nl can be illustrated by the 5-potential model calculated data [34] for the Ne Is and 2s photoionization cross sections from Ne C60, see Figure 5. 

For outer subshells of the encaged atom, the ionization thresholds of which vary from a few eV to a few tens eV, the dynamical-cage model is required. The photoionization cross section of the encaged atom in the dynamical-cage approximation will be marked with a tilde sign 5 s and... 

Figure 18 Calculated [33] RPAE results for the Xe 5s photoionization cross section of Xe Cgo obtained in the A-potential model at the frozen-cage approximation level. (a) o 1" A iro), complete RPAE calculation accounting for interchannel coupling between photoionization transitions from the Xe 4d10, 5s2 and 5p6 subshells (b) 5 A ( >), the same as in (a) but with the 4d - f, p transitions being replaced by those of free Xe, for comparison purposes (c) o AA(

The a s are the relative photoionization cross-sections of a parti( ular atomic subshell they have been obtained by a fitting procedure on reference systems. 

The calculations of the photoionization cross section of the atomic subshell have previously been performed using Hartree-Fock-Slater one-electron model by several workers. Table 1 compares the photoionization cross sections of the atomic orbital electrons obtained in the present work with those previously reported by Scofield for some atoms. Scofield has used the relativistic wave functions. The... 

The value of the photoionization cross section varies for a different photon energy. Figure 2 plots the photoionization cross sections of the atomic orbitals for Fe atom as a function of the photon energy. Yeh and Lindau have reported the photoionization cross sections of atomic subshells for various photon energies. The present result is in a good agreement with the previous calculations. 

Whenever an orbital does not have spherical symmetry (quantum number 10) any subshell splits into two levels with quantum numbers j = 1 s. This splitting is therefore increasing with the atomic number on a given subshell (constant n, 1) and with a decrease in 1 at constant n. Assuming the two levels have the same photoionization cross-section, the ratio of peak areas in the doublet is given by the ratio of their degeneracies (2j -i- 1). 

Fig. 4. Calculated photoionization cross sections for several atomic subshells in cerium as a function of photon energy (Yeh and Lindau 1985).

Usually the photoionization cross section of 5s-electrons in xenon serves as an example of the very significant role of cprrela--tions. As is known, 5s-electrons are strongly effected by their neighbours 5p and 4d subshells and are completely collectivised, their photoionization cross section being even qualitatively different from the single-particle picture - Fig. 4. 

Fig. 3, Photoionization cross section of the 3s subshell of argon, R-matrix, Burke and Taylor, ref, 6 BPAE, Amusia and Cherepkov, ref. 7 SRPA, approximate RPAE calculation by Lin, ref, 49 HF-L, Kennedy and Manson, ref, 50 expt o Houlgate et al, ref. 51 Samson and Gardner, ref, 52,...

Fig. 4. Photoionization cross section for the 5s subshell of xenon. Expt o Samson and Gardner, ref. 52 x West et al,...

Examples of Subshell Theoretical Photoionization Cross Sections of Pd. 

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