Definition:
The displacive distortion of a given rigid group is not
completely described by _atom_site_displace_Fourier_. The rigid
rotation of the group around a given axis passing through a fixed
point (for example, the centre of mass of the group) is usually
parameterized by Fourier series. Each term of the series
commonly adopts two different representations: the sine-cosine
form,
Rc cos(2\p k r)+Rs sin(2\p k r),
and the modulus-argument form,
|R| cos(2\p k r+\y),
where k is the wave vector of the term and r is the atomic
average position. _atom_site_rot_Fourier_param_modulus is the
modulus (|R|) in degrees of the complex amplitude corresponding
to the Fourier term defined by
_atom_site_rot_Fourier_atom_site_label,
_atom_site_rot_Fourier_axis and
_atom_site_rot_Fourier_wave_vector_seq_id.
Appears in list containing _atom_site_rot_Fourier_param_id
The permitted range is 0.0 -> infinity
Enumeration default: 0.0
Type: numb
Category: atom_site_rot_Fourier_param
Copyright © 2005 International Union of Crystallography