Tossup

EADP and AFIX are constraints employed while analyzing data from this technique to prevent anisotropic thermal factors from going negative. In some analysis pipelines for this technique, Fourier-transformed factors below a threshold charge are multiplied by -1 and iteratively recalculated in a dual-space algorithm called charge flipping. George Sheldrick created the ShelX program (10[1])for analyzing data from this technique, whose data can be analyzed (10[1])either with direct methods (10[1])or by correcting using Patterson functions. (10[5])This technique’s data can be analyzed with the Olex2 package, although it can be complicated by twinning. Data from this technique (10[1])must correct (10[1])for the phase (10[1])problem (10[3])before it can be used (10[2])to “solve” for electron densities. For 10 points, (-5[1])name this technique that uses Bragg’s law (10[1])and (10[2])radiation (10[1])to determine molecular structures. ■END■ (10[1])

ANSWER: X-ray crystallography [accept X-ray diffraction; accept XRD or XRC; prompt on diffraction or crystallography]
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