Index

Modulated structures dictionary (msCIF) version 3.2.1

_atom_site_U_Fourier_param.cos

Definition:

   

      The modulation of the ADP is usually
      parameterized by Fourier series. Each term of the series
      commonly adopts two different representations: the sine-cosine
      form,
           U(ij)c cos(2\\p k r)+U(ij)s sin(2\\p k r),
      and the modulus-argument form,
           |U(ij)| cos(2\\p k r+\\c),
      where k is the wave vector of the term and r is the atomic
      average position. _atom_site_U_Fourier_param.cos is the cosine
      coefficient [U(ij)c], in angstroms squared, corresponding to
      the Fourier term defined by
      _atom_site_U_Fourier.atom_site_label,
      _atom_site_U_Fourier.tens_elem and
      _atom_site_U_Fourier.wave_vector_seq_id.

Type: Real

Units: angstrom_squared

Evaluation method:

      With  p  as  atom_site_U_Fourier_param

       atom_site_U_Fourier_param.cos =  p.modulus*Cos(TwoPi*p.phase)

Category:
atom_site_U_Fourier_param