>The question is, as I rephrased it, assuming we are able to measure the 
>diffraction pattern of a single molecule with acceptable accuracy and 
>precision (comparable to what we have now for the common crystals), is it 
>better than we measure the diffraction spots from a crystal, given that the 
>spots are just a sampling of the continuous pattern from a single molecule and 
>there is loss of information in the space between the spots that are not 
>sampled by the lattice? Of course this is more of a thought experiment, so we 
>don't need to consider that all measurement is discrete in nature owing to the 
>limitation of the pixel size. I kinda agree with him and I have a feeling that 
>this is related to the sampling theorem. I do appreciate your valuable 
>comments. If this is not true, why? If this is true, what is its effect on 
>electron density?

This question depends on how you set your criteria for the goodness of the 
single-molecule data; in a way by saying the data quality is comparable to 
crystals, the question is tautological, since the cases would by stipulation be 
the same. If you mean the resolution would be equal, and all amplitudes would 
be of SNR similar to crystal data, of course the continuously-sampled version 
would be far better. There would be no phase problem (sampling theorem), and 
maps would be outstanding.

This type of thing was, I think, the original vision of the XFEL projects—you 
could check out those early papers for more details.

JPK


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