On 23 May 2008, at 02:03, Bernhard Rupp wrote:
Dear All,
I have a 3 minor questions re refmac internals:
1) does refmac use angle values directly or restrain 1-3
distances for angle restraint setup?
Yes. Angles are angles in degrees.
2) the ML coefficients FWT and DELFWT - are they the complete
Fourier coefficients including the exponential, i.e. for example
FWT = (2mFo-DFc)*exp(i*phwt)? (acc. to Murshudov & Cie 1997
actad 53 p246 formula(20) they are).
FWT (similarly DELWT) is amlitude of 2mFo exp(i phi_comb) - D |Fc| exp
(i phi_c) and PHWT is the corresponding phase.
But I cannot reconcile that with what mtz2various does when it
generates maps for xtalview. It writes hkl FWT and PHWT.
This makes only sense when the ML coefficents FWT
are only the 2mFo-DFc part excluding exp(i*phwt), because the
FT computes FWT*exp(i*PHWT)*exp(-2Pihx).
Sign has already been taken into account
I think the equal sign in (20) is confusing.
3) what happens if 2mFo-DFc < 0? Use |2mFo-DFc| and turn the
phase around i.e. phwt=phic+180? Where could I find a reference
for that?
Yes. But there is no reference.
Thx, br
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Bernhard Rupp
001 (925) 209-7429
+43 (676) 571-0536
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