occ::crystal::XrayFormFactor Struct Reference

A neutral-atom or ion X-ray form factor from Waasmaier & Kirfel (1995). More...

#include <xray_form_factors.h>

Public Member Functions
double	at_stol_sq (double stol_sq) const
	f(s), in electrons.

Public Attributes
float	a [5]
float	b [5]
float	c

Detailed Description

A neutral-atom or ion X-ray form factor from Waasmaier & Kirfel (1995).

Acta Cryst. A51, 416-431, doi:10.1107/S0108767394013292: five Gaussians plus a constant, valid to sin(theta)/lambda = 6 A^-1 (International Tables' own fit only reaches 2).

Note

The coefficients are held in single precision. That is not an oversight: cctbx stores this table as float, and matching its structure factors bit for bit means rounding the same way. The published values carry more digits than a float holds, so a handful of the literals below differ from the paper in the eighth significant figure.

Member Function Documentation

at_stol_sq()

double occ::crystal::XrayFormFactor::at_stol_sq

(

double

stol_sq

)

const

f(s), in electrons.

Parameters

stol_sq

(sin(theta)/lambda)^2 in A^-2, i.e. |G|^2/4.

Member Data Documentation

a

float occ::crystal::XrayFormFactor::a[5]

b

float occ::crystal::XrayFormFactor::b[5]

c

float occ::crystal::XrayFormFactor::c

---

The documentation for this struct was generated from the following file:

• /home/runner/work/occ/occ/include/occ/crystal/xray_form_factors.h