Figure 3
Another example of a congested spot pattern, the case of the large-angle oscillation technique (LOT) diffraction (from Weisgerber & Helliwell, 1993. Reproduced with permission of the Royal Society of Chemistry.). (a) The principle behind LOT; the rotation of the crystal beyond the typical dmin/maximum unit-cell dimension is not in fact limiting as the Bragg angles of these two reciprocal lattice points (h, k, l and h + 1, k, l) are slightly different. (b) LOT practice; a 90° rotation X-ray diffraction photograph recorded at SRS station 9.5, wavelength ∼1 Å from concanavalin A saccharide-free crystal form space group I222, unit-cell dimensions a = 88, b = 86, c = 62 Å, diffraction resolution at the edge is 5 Å (higher resolution, dmin = 3 Å, randomly set crystal diffraction pattern examples are also given in Weisgerber & Helliwell, 1993). |