Discussion List Archives

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: polarization

I use the polarization that Wolfgang Kabsch defined in his 1988 paper.
It consists of the degree of polarization and a vector which defines
a normal to the plane of polarization.  So core CIF almost has it with
this vector implicit.  The vector is defined is terms of the lab
coordinate system (remember the MSC system?).

Jim

> One thing I haven't seen in the imgCIF/CBF dictionary is a suitable data
> item for the beam polarization - the core CIF item seems to be based on a
> four-circle diffractometer equipped with a point detector, as the
> polarization is referenced to "the normal to the diffraction plane of the
> sample (i.e. the plane containing the incident and reflected beams)."
> (from http://www.iucr.org/iucr-top/cif/home.html#dics, section on
> _diffrn_radiation_polarisn_ratio). 
> 
> Would it be more sensible in the case of area detectors to have a
> definition based on "gravity" (or something more rigorous?).

Yes, see above.

Reply to: [list | sender only]
International Union of Crystallography

Scientific Union Member of the International Science Council (admitted 1947). Member of CODATA, the ISC Committee on Data. Partner with UNESCO, the United Nations Educational, Scientific and Cultural Organization in the International Year of Crystallography 2014.

International Science Council Scientific Freedom Policy

The IUCr observes the basic policy of non-discrimination and affirms the right and freedom of scientists to associate in international scientific activity without regard to such factors as ethnic origin, religion, citizenship, language, political stance, gender, sex or age, in accordance with the Statutes of the International Council for Science.

Useful links