[phenixbb] neutron scattering table for specific metal isotope

[Pavel Afonine]

Hi Leif,

> I thought this would be simple, but this is nowhere near as clear as 
> finding the values for X-rays and electrons.

it took me a few seconds to find it, although I believe I have an 
advantage of working with this code for about 11 years -;)

Neutron:
cctbx_project/cctbx/eltbx/neutron.cpp

Electron: same directory, look for files with "electron" in names.

Xray:
cctbx_project/cctbx/eltbx/xray_scattering

Note, for Xray there are 3 choices available: it1992 (form-factors from 
Intl.Tabl. 1992), wk1995 (D. Waasmaier & A. Kirfel. Acta Cryst. (1995). 
A51, 416-431. "New analytical scattering-factor functions for free atoms 
and ions") and n_gaussian, which is a N-gaussian dynamic approximation 
to the table data and that is used by default.

> Where is the neutron_news_1992_table located in the code?
> Is there anyway to redefine the scattering for specific isotopes?

See my reply to Maxime's email.

> And why use these values over those published by Rauch and Waschkowski 
> in the Neutron Data Booklet (2003), other than the horribly small print?

I didn't get this.. Could you please explain what you mean? We added 
neutron scattering table well before we even planned to add neutron 
refinement option to phenix.refine. If you think there is a better 
option then I am happy to add it.

Pavel