Re: anisotropic B factors

["Eleanor J. Dodson" <ccp4@yorvic.york.ac.uk>]

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> 
> Theres a paper by Murshudov et al (Acta Cryst.D55 1999 pp. 247) where they
> do some tests on this.
> 
> Does anyone know how to get the Overall anisotropic Uii values for the
> crystal, when SCAL TYPE ANIS   was used?
> 



 There are some notes that I made in the $CLIBS/rwbrook.f on the
transformations..

C
C  PDB files contain anisotropic temperature factors as orthogonal Us.
C The anisotropic temperature factors can be input/output to this
routine
C  as orthogonal or as crystallographic Us.
C 
C  Shelx defines Uf to calculate temperature factor as:
C T(aniso_Uf) = exp (-2PI**2 ( (h*ast)**2 Uf_11 + (k*bst)**2 Uf_22 + ...
C                            + 2hk*ast*bst*Uf_12 +..)
C
C   Note:   Uo_ji == Uo_ij and  Uf_ji == Uf_ij.
C
C  [Uo_ij] listed on ANISOU card satisfy  the relationship:
C  [Uo_ij] =   [RFu]-1 [Uf_ij] {[RFu]-1}T   C
C        where [Rfu] is the normalised [Rf] matrix read from the SCALEi
cards.
C        see code.   [ROu] ==  [RFu]-1
C##################################################
C     Generate ROU and RFU for AnisoU stuff
       IF (MATRIX) THEN
         RFU(4,4) = 1.0
         DO I = 1,3
         FAC= SQRT(RF(I,1)*RF(I,1) + RF(I,2)*RF(I,2) +
     +              RF(I,3)*RF(I,3))
         RFU(I,1) = RF(I,1)/FAC
         RFU(I,2) = RF(I,2)/FAC
         RFU(I,3) = RF(I,3)/FAC
         RFU(I,4) = 0.0
         RFU(4,I) = 0.0
         END DO
C   Get the Inverse of RFU
         CALL RBRINV(RFU,ROU)
       END IF
C
C#################################################
C T(aniso_Uo) = U(11)*H**2 + U(22)*K**2 + 2*U(12)*H*K + ...
C where H,K,L are orthogonal reciprocal lattice indecies. ( EJD: I
think????)
C
C Biso     = 8*PI**2 (Uo_11 + Uo_22 + Uo_33) / 3.0
C
C   [Uf(symm_j)] = [Symm_j] [Uf] [Symm_j]T
C


 Here Uo is the orgthoganal correction and Uf the fractional one.

 As long as the orthogonalisation code is the conventional one, you can
get the the same transformations from int Tab, but this works whatever
the SCALEi cards define as the orthogonalisation..

  Eleanor
-- 
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Eleanor J.Dodson, Chemistry Department, University of York, U.K.
Tel: Home +44 (1904) 42 44 49, work:  +44 (1904) 43 25 65
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