The left model shows a GaInN cluster a few unit-cells across. A "flat Ewald slice" (kinematic electron diffraction pattern) of its corresponding reciprocal lattice is on the right. The bright central spot in the reciprocal space model is the "DC peak" (unscattered beam). Camera constant for the diff pat is 1000 [pmA], meaning that you divide the spot measurement in pm (pattern model units obtained by double-clicking spot pairs with ZOLZ toggled to show the full reciprocal lattice) into 1000 to get the corresponding d-spacing in Angstroms.
Challenge: Try capturing a <110> zone diffraction pattern, and indexing the spots in it. This calculator might come in handy if you first type two numbers (e.g. 10 and 100) that multiply to 1000 into the calibration text boxes so that pattern model units substitute for mm.
Here's a thin specimen HREM image of GaInN* viewed perpendicular to (110) and (001) that Martin and I put together in our first attempt at using Kirkland's routines. Question: Do the nitrogen atoms scatter too weakly to be seen easily? /pf
Here I've taken an experimental image region from the top left of negative 5639 (likely GaInN), band-pass filtered it using 6 periodicity pairs plus the DC peak to minimize contrast from overlying mill damage, and then superposed on it in red the simulated (thin slice) image above. How well do you think model and experiment agree? This too is only a first pass, with questions of superlattice anti-phase boundaries and evidence for nitrogen atom columns still open. /pf