Accurate structure factor determination using

Accurate structure factor determination using 100 keV synchrotron radiation... 

Vibrational frequencies of hexatriene and octatetraene have been reported by several authors21,24-26,36. The increase in the size of these molecules with respect to butadiene limits the use of highly accurate levels of calculation, so that a good choice of scaling factors is necessary to obtain useful results. Kofraneck and coworkers21 have shown that employing scale factors determined from vibrational data for trans structures alone does not give a balanced description of cis and trans structures. 

Such a refinement program was very useful in these cases but is in general of limited application, for it is only with very simple structures (both nuclear and magnetic) that a sufficient number of nuclear intensities can be accurately resolved at 4.2K to provide a basis for refinement and the determination of the scale factor. A more general refinement procedure has been recently introduced (69) which fits the measured profile of the powder diffraction pattern rather than individual intensities or structure factors. With data of high resolution obtained over a wide... 

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