The report, titled "X-Ray Scattering Factors Computed from Numerical Hartree-Fock Wave Functions," was prepared by Don T. Cromer and Joseph B. Mann for the Los Alamos Scientific Laboratory of the University of California, Los Alamos, New Mexico. It was sponsored by the United States Atomic Energy Commission and distributed on March 11, 1968. The report presents the results of calculations on X-ray scattering factors for neutral atoms from helium to lutetium (He to Lu) and for most chemically significant ions up to lutetium hexachloride (Lu³⁺). These factors were computed using numerical Hartree-Fock wave functions and are provided in numerical tables and as coefficients for an analytic function. The authors compared their results with those from other models, including the Thomas-Fermi-Dirac model, the Hartree model, the Hartree-Fock-Slater (HFS) model, and the Dirac-Slater (DS) model. They found that the Hartree-Fock (HF) model, except for relativistic effects, provides the best approximation for free atoms. The HF scattering factors for elements up to krypton (Z = 36) have been previously computed, and the results are tabulated by Ibers. Mann's recent extensive calculations of numerical HF wave functions were used to compute the X-ray scattering factors for all neutral atoms up to lutetium (Z = 103) and most chemically significant ions up to lutetium (Z = 71). The scattering factors were calculated for angles from sin θ/λ = 0 to 1.50 Å⁻¹ with intervals of 0.01 Å⁻¹. The detailed results are presented in Table I, and the coefficients and maximum errors for the analytic approximation are listed in Table II. The report also discusses the importance of relativistic effects, noting that the HFS and DS scattering factors are essentially identical up to Z ≈ 40 and differ only slightly for heavier elements. For heavier elements, the authors suggest that scattering factors calculated from a relativistic HF model should lie between the HF and DS scattering factors. However, until relativistic HF scattering factors are available, the HF or DS scattering factors can be used equally well for heavy elements. The report includes references to previous work and provides a detailed breakdown of the scattering factors for various elements, including their configuration and the coefficients used in the analytic approximation.The report, titled "X-Ray Scattering Factors Computed from Numerical Hartree-Fock Wave Functions," was prepared by Don T. Cromer and Joseph B. Mann for the Los Alamos Scientific Laboratory of the University of California, Los Alamos, New Mexico. It was sponsored by the United States Atomic Energy Commission and distributed on March 11, 1968. The report presents the results of calculations on X-ray scattering factors for neutral atoms from helium to lutetium (He to Lu) and for most chemically significant ions up to lutetium hexachloride (Lu³⁺). These factors were computed using numerical Hartree-Fock wave functions and are provided in numerical tables and as coefficients for an analytic function. The authors compared their results with those from other models, including the Thomas-Fermi-Dirac model, the Hartree model, the Hartree-Fock-Slater (HFS) model, and the Dirac-Slater (DS) model. They found that the Hartree-Fock (HF) model, except for relativistic effects, provides the best approximation for free atoms. The HF scattering factors for elements up to krypton (Z = 36) have been previously computed, and the results are tabulated by Ibers. Mann's recent extensive calculations of numerical HF wave functions were used to compute the X-ray scattering factors for all neutral atoms up to lutetium (Z = 103) and most chemically significant ions up to lutetium (Z = 71). The scattering factors were calculated for angles from sin θ/λ = 0 to 1.50 Å⁻¹ with intervals of 0.01 Å⁻¹. The detailed results are presented in Table I, and the coefficients and maximum errors for the analytic approximation are listed in Table II. The report also discusses the importance of relativistic effects, noting that the HFS and DS scattering factors are essentially identical up to Z ≈ 40 and differ only slightly for heavier elements. For heavier elements, the authors suggest that scattering factors calculated from a relativistic HF model should lie between the HF and DS scattering factors. However, until relativistic HF scattering factors are available, the HF or DS scattering factors can be used equally well for heavy elements. The report includes references to previous work and provides a detailed breakdown of the scattering factors for various elements, including their configuration and the coefficients used in the analytic approximation.