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Macromolecular dictionary (mmCIF) version 2.0.09




   The [3][3] element of the standard anisotropic atomic
   displacement matrix U, which appears in the structure-factor
   term as:

   T = exp{-2 pi^2^ sum~i~[sum~j~(U^ij^ h~i~ h~j~ a*~i~ a*~j~)]}

   h  = the Miller indices
   a* = the reciprocal space cell lengths

   These matrix elements may appear with atomic coordinates
   in the ATOM_SITE category, or they may appear in the separate
   ATOM_SITE_ANISOTROP category, but they may not appear in both
   places. Similarly, anisotropic displacements may appear as
   either B's or U's, but not as both.

   The unique elements of the real symmetric matrix are
   entered by row.

Type: float

Type conditions: esd

Mandatory item: no

Related items: _atom_site.aniso_U[3][3]_esd (associated_esd)
_atom_site.aniso_B[3][3] (conversion_constant)
_atom_site_anisotrop.B[3][3] (conversion_constant)
_atom_site.aniso_B[3][3] (alternate_exclusive)
_atom_site_anisotrop.B[3][3] (alternate_exclusive)
_atom_site_anisotrop.U[3][3] (alternate_exclusive)

Category: atom_site