Shell Effects in the Relaxation Energy of 1s-Core Ionization of Atoms from He Through Xe

Israel Journal of Chemistry

Kuleff

Delchev

et al. 2004

In this paper we investigate the variation, along the periodic table, of 2s-core ionization energies, using both relativistic and non-relativistic calculations. We show that electron relaxation energies display variations typical of the shellfilling process, while their relativistic contributions show specifically distorted shell features. Just as for the 1s-core ionization energies, investigated earlier, the sensitivity of these differential properties to the shell-filling process may be used as a probe of the accuracy of calculations of core ionization energies. Discrepancies with experimental results are critically analyzed.

Section: Resultsmentioning

confidence: 99%

“…In this paper, as in a previous paper on 1s-core ionization energies, 24 we investigate the degree of dependence of the relaxation energy in a 2s-core ionization on the shell-filling process. This term expresses the perturbation of the electron cloud by the presence of the core hole and is a function of the whole electron distribution.…”

Section: Introductionmentioning

confidence: 99%

Shell Effects in the Relaxation Energy of 2s‐Core Ionization of Atoms from B through Xe

Israel Journal of Chemistry

Kuleff

Delchev

et al. 2004

“…For elements from Ar to Ba (excluding transition elements), we have computed the nonrelaxed and relaxed core ionization energies for the single 1s, 2p 1/2 , and 2p 3/2 and double 1s‐2p 1/2 and 1s‐2p 3/2 ionizations, using procedures similar to those used in earlier papers 14–17.…”

Section: Computations and Resultsmentioning

confidence: 99%

“…In previous papers 14–17 we have investigated the relaxation and relativity effects in the 1s 14, 16, 2s 15, 16 and 2p 16, 17 core ionization energies of neutral atoms in the series LiXe, BXe, and ClBa. Owing to shell effects 18, 19, the variations of the energy contributions with atomic number Z are not monotonous but involve an irregular oscillating part.…”

Section: Introductionmentioning

confidence: 99%

“…In earlier work 27 we have tried to relate two satellites observed in the XPS near‐edge spectrum of SF 6 to (1s, 2p) “singlet” and “triplet” double‐core excitations, using a procedure of progressive corrections to simpler computations that was to be developed in later papers 14–17. The contribution of “cross relaxation,” due to the simultaneous occurrence of two core holes, played an important role in the methodology that we used.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Electron cross relaxation as a function of single relaxation contributions in double‐core ionization energies and spin–orbit splitting of atoms from Ar to Ba. I. 1s⁻2p⁻ double‐core holes

Int J of Quantum Chemistry

Bonnelle

2007

ABSTRACT:On the basis of numerical ab initio, delta and multiconfiguration BreitDirac-Fock (⌬BDF and MCBDF) computations, we have investigated the dependence of electron "cross relaxation" on the single relaxation contributions in double-core ionization energies and spin-orbit splitting of atoms from Ar to Ba, excluding transition elements. The cross-relaxation variation with Z was fitted to a quadratic function of the geometric average of the single relaxation contributions. For the family of atoms AlOCl, it was found that the splitting of the levels is not a straight measure of 2p spin-orbit coupling. The families of "light" atoms ArOCa and CuOSr yielded together a set of best-fit coefficients, while the family of heavier atoms AgOBa yielded another set. The best-fit functions were used to predict double-core ionization energies from single ionization data and from Koopmans' values for atoms from Ar to Ba. For molecules a semiempirical expression is proposed.

Ansatz for the evaluation of the relativistic contributions to core ionization energies in complex molecules involving heavy atoms

Int J of Quantum Chemistry

Kuleff

Chong

et al. 2005

Self Cite

ABSTRACT:On the basis of numerical, ab initio ⌬DF and ⌬HF computations of 1s-core, 2s-core, and 2p-core ionization energies of atoms, from Li through Xe, an allometric empirical formula that was proposed for evaluating relativistic corrections (including QED effects) to nonrelativistic values is assessed for homogeneous sets of elements in the periodic table. The two coefficients involved in this formula are precisely determined for 1s-core ionization in the sets of atoms Be-Ne, Mg-Ar, Zn-Kr, and Cd-Xe; 2s-core ionization in the sets of atoms Mg-Ar, Zn-Kr, and Cd-Xe; and 2p-core ionization in the set Mg-Ar. It is shown that the medium relative error on the results obtained using this formula, with respect to those directly computed, decreases from a few percent to a few hundredths of 1% when the depth of the ionized level increases. This formula could be used to include relativistic (and QED) corrections to results yielded by simpler, nonrelativistic calculations on complex molecules involving heavy atoms.