On 01/13/12 09:53, Jacob Keller wrote: > No, I meant the non-lattice-convoluted pattern--the pattern arising > from the Fourier-transformed electron density map--which would > necessarily become more complicated with larger molecular size, as > there is more information to encode. I think this will manifest in > what James H called a smaller "grain size."
I've been thinking about these matters recently and had a nifty insight about exactly this matter. (While this idea is new to me I doubt it is new for others.) The lower limit to the size of the features in one of these "scattergrams" is indicated by the scattergram's highest frequency Fourier component. Its Fourier transform is the Patterson map. While we usually think of the Patterson map as describing interatomic vectors, it is also the frequency space for the diffraction pattern. For a noncrystalline object the highest frequency component corresponds to the longest Patterson vector or, in other words, the diameter of the object! The bigger the object, the higher the highest frequency of the scattergram, and the smaller its features. Dale Tronrud > > JPK > > On Fri, Jan 13, 2012 at 11:41 AM, Yuri Pompeu <yuri.pom...@ufl.edu> wrote: >> to echo Tim's question: >> If by pattern you mean the position of the spots on the film, I dont think >> they would change based on the complexity of the macromolecule being >> studied. As far I know it, the position of the spots are dictated by the >> reciprocal lattice points >> (therefore the real crystal lattice) (no?) >> The intensity will, obviously, vary dramatically... >> ps. Very interesting (cool) images James!!! > > >
