### Abstract

Tabulations are presented of relativistic Hartree‐Fock atomic form factors*F* (*x*,*Z*), for values of *x* (=sin(ϑ/2)/λ from 0.01 to 10^{9} Å^{−1}, for all elements *Z*=1 to 100. For *Z*=1, *F* (*x*,*Z*) is given by the exact expression of Pirenne. For *Z*=2 to 98, *x*=0.01 to 2.0 Å^{−1}, the tabulated values are those of Cromer and Waber given in the *I* *n* *t* *e* *r* *n* *a* *t* *i* *o* *n* *a* *l* *T* *a* *b* *l* *e* *s* *f* *o* *r* *X*−*R* *a* *y* *C* *r* *y* *s* *t* *a* *l* *l* *o* *g* *r* *a* *p* *h* *y* (Vol. IV, 1974), based in part on the work of Doyle and Turner. For *Z*=21 to 92, *x*=2.2 to 6.0 Å^{−1}, the present tables are based on the values of Doyle and Turner and additional values (*Z*=44,60,68, and 74) as given by O/verbo/. For *Z*=3 to 20.*x*=2.2 to 45 Å^{−1}, *Z*=21 to 92,*x*=62 to 45 Å^{−1} the tables are interpolated from values given for 36 elements by O/verbo/, extended to *x*=10^{9} Å^{−1} using O/verbo/’s corrections to the Bethe‐Levinger *K*‐shell expression. The remainder of the table is filled in by interpolation and extrapolation, guided for high *x*‐values by the Bethe‐Levinger result. Tables of relativistic coherent (Rayleigh) scattering cross sections, obtained by numerical integration of the Thomson formula weighted by *F* ^{2}(*x*,*Z*), are presented for all elements *Z*=1 to 100, for photon energies 100 eV (λ=124 Å=12.4 nm) to 100 MeV (λ=0.000 124 Å=12.4 fm). Departures from the nonrelativistic coherent scattering cross sections tabulated in J. Phys. Chem. Ref. Data 4, 471 (1975) are less than 1% for *Z*<20. However for a high‐*Z* element such as lead, for example, the relativistic coherent scattering cross section is systematically higher by less than 0.4% below 1 keV, by 8% at 100 keV and by 13% above 1 MeV.

© 1979 American Institute of Physics for the National Institute of Standards and Technology

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