Elastic Photon-Atom Scattering

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RTAB: the Rayleigh scattering database

Interactively generate tables of:
Anomalous Scattering Factors | Cross Sections.

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Abstract

Elastic photon scattering is an important tool for obtaining information about the structural properties of matter. The programs and data presented here are useful for evaluating Rayleigh scattering, the contribution to elastic scattering made by the bound electrons of an atom. Rayleigh scattering dominates elastic scattering for most of the x-ray and low-energy gamma-ray regimes. Most of the data available at this site are based on the anomalous-scattering-factor (ASF) approximation, although more sophisticated S-matrix predictions are available as data files. For a more detailed discussion of these and other approximations to scattering, see

"Validity of Form-Factor, Modified-Form-Factor and Anomalous-Scattering-Factor Approximations in Elastic Scattering Calculations," by Lynn Kissel, B. Zhou, S. C. Roy, S. K. Sen Gupta and R. H. Pratt, Acta Crystallographica A51, 271-288 (1995).

"New Relativistic S-Matrix Results for Scattering - Beyond the Usual Anomalous Factors/Beyond Impulse Approximation," by R. H. Pratt, Lynn Kissel and P. M. Bergstrom, Jr., in Resonant Anomalous X-Ray Scattering, edited by G. Materlik, C. J. Sparks and K. Fischer (North-Holland: Amsterdam, 1994).

"Elastic Scattering of Gamma-Rays and X-Rays by Atoms," by P. P. Kane, Lynn Kissel, R. H. Pratt and S. C. Roy, Physics Reports 140, 75-159 (1986).

"Rayleigh Scattering - Elastic Photon Scattering by Bound Electrons," by Lynn Kissel and R. H. Pratt, in Atomic Inner-Shell Physics, edited by Bernd Crasemann (Plenum Publishing: New York, 1985).

Generate Tables

Direct access to anomalous scattering factors for your choice of atom and photon energy.
Generate differential and total cross sections for elastic scattering based on form factors and angle-independent anomalous scattering factors.

Data Files

Also see ftp://www-phys.llnl.gov/pub/rayleigh/README.txt for additional information.

You may directly access text files containing differential elastic scattering tables on a relatively dense grid in scattering angle (97 points on 0-180 degrees), photon energy (56 points on 0.0543-2754 keV), and atomic number (all Z on 1-99). These data are available via anonymous ftp from

ftp://www-phys.llnl.gov/pub/rayleigh/

stored in files with names of the form

model[+NT]_zzz

where

model - model for Rayleigh amplitudes

SM => S-matrix method for inner-electrons

MFASF => MF w/angle-independent anomalous scattering factors

RFASF => MF w/angle-independent anomalous scattering factors

MF => modified relativistic form factors, g(q)

RF => relativistic form factors, f(q)

NF => non-relativistic form factors, f(q), Hubbell et al. (1975)

+NT - optional, indicates that nuclear Thomson amplitudes are included