3.8: Cromer–Mann coefficients
The set of nine coefficients \(a_i, b_i, c\, (i=1,\dots, 4)\) in a parameterization of the non-dispersive part of the atomic scattering factor for neutral atoms as a function of (sinθ) / λ :
\(f^0(\sin\theta/\lambda) = \sum_{i=1}^4 a_i \exp[-b_i(\sin\theta/\lambda)^2] + c\)
for \(0 < (\sin\theta)/\lambda < 2.0\,\mathrm{\AA}^{-1}\).
This expression is convenient for calculation in crystal structure software suites.