RTAB data files are available at:
ftp://www-phys.llnl.gov/pub/rayleigh/RTAB

11. Selected source codes (code)

• RSCF - our modified version of HEX (Liberman et al., 1971), a relativistic Dirac-Slater self consistent potential. These potentials are the basis of all of our further elastic scattering calculations. RSCF was used to produce the files in the 'data_SCF' folder of RTAB.

• FORM - our relativistic form-factor code. FORM easily computes subshell, shell and total-atom relativistic form factors and modified relativistic form factors, using the potential supplied by RSCF. FORM was used to produce the files in the 'data_MF' and 'data_RF' folders of RTAB.

• BBT - our evaluation of relativistic multipole bound-bound oscillator strengths, using the potential supplied by RSCF. BBT was used to produce the files in the 'data_BBT' folder of RTAB.

• GPRIME - our relativistic anomalous scattering code. GPRIME requires input photoeffect cross sections, bound-bound oscillator strengths, and a potential. GPRIME generated the files in the 'data_ASF' folder of RTAB.

• ASFTAB - computes the energy-dependent part of the bound-bound contribution to the anomalous scattering factors, and reformats the files in 'data_ASF'. ASFTAB was used to prepare the files in the 'tables_ASF' folder of RTAB.

• FFTAB - computes elastic scattering cross sections based on the form-factor approximation, optionally including anomalous scattering factors. FFTAB can
  • utilize any of the form factors in 'data_MF', 'data_RF' or 'data_NF' (i.e., modified relativistic form factors, relativistic form factors, or non-relativistic form factors);

  • it can tabulate differential or integrated scattering cross sections;

  • it can evaluate unpolarized, linearly polarized (parallel or perpendicular), or circularly polarized (spin-flip or no-spin-flip) cross sections;

  • it can included anomalous scattering corrections, assuming angle independence or an angle dependence based on that of the non-relativistic Coulomb K shell (Bergstrom et al, 1997).

• RAYLIB - contains a collection of utility and support subprograms. RAYLIB contains all the support routines needed by the other codes listed here.

Potential users may be particularly interested in the FFTAB code. As noted earlier, modified relativistic form factors with angle-independent anomalous scattering factors (MFASF) produce results close to those from our S-matrix prescription (SM) in many cases. MFASF cross sections at arbitrary photon energy, utilizing the data stored in the RTAB database, are easy to produce with FFTAB. This fact will be utilized for interpolation on SM values.

Another reason for potential interest in FFTAB is that it provides an avenue for easily going beyond the data stored in RTAB. Using these codes, it should be relatively easy to prepare cross sections for scattering from ions and excited atoms. With more effort it should be possible to utilize FFTAB to go beyond our SM predictions, incorporating experimental information (such as experimental binding energies) or atomic environment effects (as for scattering in plasmas or solids) in more realistic scattering calculations.

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Information date: Sep. 2, 2000 lk