Index

Modulated structures dictionary (msCIF) version 3.2.1

_atom_site_displace_Fourier_param.phase

Name:
_atom_site_displace_Fourier_param.phase

Alias:
_atom_site_displace_Fourier_param_phase

Definition:

   

      The displacive distortion of a given atom or rigid group (see
      also _atom_site_rot_Fourier_param.phase) is usually parameterized
      by Fourier series. Each term of the series commonly adopts two
      different representations: the sine-cosine form,
           Ac cos(2\\p k r)+As sin(2\\p k r),
      and the modulus-argument form,
           |A| cos(2\\p k r+\\f),
      where k is the wave vector of the term and r is the atomic
      average position. _atom_site_displace_Fourier_param.phase is the
      phase (\f/2\\p) in cycles of the complex amplitude corresponding\
      to the Fourier term defined by
      _atom_site_displace_Fourier.atom_site_label,
      _atom_site_displace_Fourier.axis and
      _atom_site_displace_Fourier.wave_vector_seq_id.

Type: Real

Units: cycles

The permitted range is -1.0 → 1.0

Enumeration default: 0.0

Evaluation method:

      With  p  as  atom_site_displace_Fourier_param

       atom_site_displace_Fourier_param.phase =  Phase(Complex(p.cos,-p.sin)/2/Pi

Category:
atom_site_displace_Fourier_param