Helical Form factor

[JDB Science LLC]

I am forwarding this reply from John Blackwell. We are working with new 
list server procedures installed by the IUCr web guys and there may be 
a little more "operator training" needed :).
From: John Blackwell <jxb6 at po.cwru.edu>
Date: November 5, 2003 10:23:56 AM EST
To: Discussion list for the Small-Angle Scattering community 
<sa_scat at iucr.org>
Subject: Re: helical ribbon


Scattering by a continuous helix was the starting point for prediction 
of
the scattering by helical molecules: Cochran Crick  and Vand, Acta
Crystallogr. 1953.

This is for an infinitessimally thick ribbon and one would need to 
convolute
this with the necessary function to allow for the thickness of the 
ribbon.

John Blackwell
Leonard Case Jr. Professor
Deaprtment of Macromolecular Science
Case Western Reserve University
Cleveland OH 44120-7202
USA
1-216-368-6370