Retardation and multipole effects in Rayleigh scattering by hydrogenlike ions at low and x-ray photon energies

Costescu, A.; Bergstrom, P. M.; Dinu, C.; Pratt, R.H.

doi:10.1103/physreva.50.1390

Cited by 24 publications

(34 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…for scattering of photons with energies up to several times the K-shell photoionization threshold from elements of low to moderate nuclear charge. Costescu et al (1994) demonstrated this explicitly by comparisons with S-matrix data.…”

Section: Fj"(w) = -(W/4zcc)crj(hw)mentioning

confidence: 90%

“…The nonrelativistic dipole approximation suffices to predict the dominant s-state photoionization across sections (Oh, McEnnan & Pratt, 1976;Ron, Goldberg, Stein, Manson, Pratt & Yin, 1994) and consequently, from (4) and (5), forward anomalous scattering amplitudes, to quite high energies. However, the results of Costescu et al (1994) made clear the importance of retardation and multipole corrections in determining the angular distribution of the scattered photons. (At the same time, it may still be supposed that, well above the K edge, K-shell contributions still dominate the full anomalous amplitudes.)…”

Section: Fj"(w) = -(W/4zcc)crj(hw)mentioning

confidence: 99%

“…N does not 6.00 contribute to the full scattering amplitude at forward 12.00 angle and, since it is not determined from the 24.00 photoeffect cross section, is normally neglected in 48.00 FF + ASF at all angles. (It is true as we will see later 96.00 274.00 that N is smaller in magnitude than M.) In order to obtain the angle dependence of the anomalous scattering factors, the full angle dependence of the amplitude M needs to be retained as does the contribution of N. Costescu et al (1994) have derived the following approximate expressions for the non-relativistic Coulomb K-shell amplitudes, using the first three terms in an expansion of the exact nonrelativistic amplitude in the parameter (kotZ sin 0/2)2:…”

Section: Formalismmentioning

confidence: 99%

“…Recently, Costescu, Bergstrom, Dinu & Pratt (1994) have greatly simplified the full nonrelativistic hydrogenic ground-state amplitude, obtaining results in a series expansion in terms of elementary functions and the dipole nonrelativistic hydrogenic ground-state amplitude that had first been obtained by Gavrila (1967). The nonrelativistic dipole approximation suffices to predict the dominant s-state photoionization across sections (Oh, McEnnan & Pratt, 1976;Ron, Goldberg, Stein, Manson, Pratt & Yin, 1994) and consequently, from (4) and (5), forward anomalous scattering amplitudes, to quite high energies.…”

Section: Fj"(w) = -(W/4zcc)crj(hw)mentioning

confidence: 99%

“…In the next section, we used the results of Costescu et al (1994) to explicitly obtain the angle dependence of the K-shell anomalous scattering factors. At energies above the K-shell ionization threshold, the total photonatom cross section and, as a consequence of (4) and (5), the anomalous scattering factors are dominated by the ionization of the K-shell electrons.…”

Section: Fj"(w) = -(W/4zcc)crj(hw)mentioning

confidence: 99%

See 4 more Smart Citations

Investigation of the Angle Dependence of the Photon–Atom Anomalous Scattering Factors

Bergstrom

Kissel²,

Pratt³

et al. 1997

Acta Cryst Sect A

Self Cite

View full text Add to dashboard Cite

The angle dependence of the elastic photon-atom scattering amplitude is investigated using full relativistic S-matrix calculations for guidance. A simple quantitative approach is developed based on the full nonrelativistic amplitude for Rayleigh scattering from the ground state of a hydrogenic ion and it is successfully applied to neutral atoms of low and intermediate nuclear charge. This framework is useful for scattering of X-rays with energies above the K-shell ionization threshold but below energies where major relativistic corrections are necessary. The generalized anomalous scattering factors presented here go beyond the usual angle-independent anomalous-scattering-factor approximation, permitting a discussion of the full angular dependence of the anomalous scattering factors. Simple formulas, expressed in terms of elementary functions and a loOkup table, are presented for these generalized anomalous scattering factors. Numerical examples illustrate that the angle dependence can be substantial. A fairly good representation of full numerical results is achieved.

show abstract

Section: Fj"(w) = -(W/4zcc)crj(hw)mentioning

confidence: 90%

Section: Fj"(w) = -(W/4zcc)crj(hw)mentioning

confidence: 99%

Section: Formalismmentioning

confidence: 99%

Section: Fj"(w) = -(W/4zcc)crj(hw)mentioning

confidence: 99%

Section: Fj"(w) = -(W/4zcc)crj(hw)mentioning

confidence: 99%

See 3 more Smart Citations

Investigation of the Angle Dependence of the Photon–Atom Anomalous Scattering Factors

Bergstrom

Kissel²,

Pratt³

et al. 1997

Acta Cryst Sect A

Self Cite

View full text Add to dashboard Cite

show abstract

Influence of Relativistic Structure and Retardation in Two-Photon Transitions in Hydrogenic Systems

Szymanowski

Véniard

Taïeb

et al. 1998

Applications of High-Field and Short Wavelength Sources

View full text Add to dashboard Cite

Toward improved photon-atom scattering predictions

Kissel

1995

Nuclear Instruments and Methods in Physics Research Section B:

View full text Add to dashboard Cite

Photon-atom scattering is important in a variety of applications, but scattering from a composite system depends on the accurate characterization of the scattering from an isolated atom or ion. We have been examining the validity of simpler approximations of elastic scattering in the light of second-order S-matrix theory. Partitioning the many-body amplitude into Rayleigh and Delbriick components, processes beyond photoionization contribute. Subtracted cross sections for bound-bound atomic transitions, bound pair annihilation, and bound pair production are required in anomalous scattering factors for: 1) convergence of the dispersion integral; 2) agreement with predictions of the more sophisticated S-matrix approach; 2) satisfying the Thomas-Reiche-Kuhn sum rule. New accurate tabulations of anomalous scattering factors have been prepared for all Z, for energies 0-10,OOO keV, within the independent particle approximation (PA) using a Dirac-Slater model of the atom. Separately, experimental atomic photoabsorption threshold information has been used to modify these P A predictions for improved comparison with experiment. *This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48. ~~~~~~~~ DISCLAIMER This report was .prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes a n y legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute o r imply its endorsement, recommendation, or favoring by t h e United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of t h e United States Government or any agency thereof. DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. :. ,

show abstract

Retardation and multipole effects in Rayleigh scattering by hydrogenlike ions at low and x-ray photon energies

Cited by 24 publications

References 17 publications

Investigation of the Angle Dependence of the Photon–Atom Anomalous Scattering Factors

Investigation of the Angle Dependence of the Photon–Atom Anomalous Scattering Factors

Influence of Relativistic Structure and Retardation in Two-Photon Transitions in Hydrogenic Systems

Toward improved photon-atom scattering predictions

Contact Info

Product

Resources

About