CrysAlis^Pro Tip

A Fourth Way to Determine Crystal Faces

Nowadays, the primary source on most single crystal diffractometers is no longer an X-ray sealed tube with a molybdenum target and nearly parallel beam, but rather a high-brilliance copper source with a beam converging to a spot smaller than two hundred microns on the crystal. With the paradigm shift of how crystals are measured in chemical crystallography, corrections based on the crystal shape become more important and often crucial for obtaining an optimal result. With longer wavelengths, absorption effects become more prominent, but even for a sample with a low linear absorption coefficient (μ), the beam profile correction has proven to be essential in many cases. There are three main tools for the interactive determination of crystal faces: drag, point, and snap. (1) Each of these has proven useful for different types of samples. But did you know there is a fourth method? And it may be the fastest one yet. Here’s how to use this fourth method:

Choose one of your favorite ways to open the Crystal Movie tool in CrysAlis^Pro. In the toolbox window, switch to the Add shape (1) tab. Select the Draw height of crystal (2) tool by ticking the checkbox next to it. Using two lines, select the top and bottom of the crystal that has been mounted on top of the loop. After that, just click Create shape (3) button and leave the rest of the work to CrysAlis^Pro.

The software will automatically identify the loop, find your sample on the loop, and generate faces automatically around the crystal in less than ten seconds using machine vision algorithms.

You can examine and edit the results on the Faces tab of the Crystal shape toolbox window. Although some faces may have higher Miller indices, the generated shape is perfect as it is for applying a beam illumination correction and even first absorption corrections for high-Z materials. Don’t forget to use the Description button to add CheckCif-required color and shape CIF entries.

You can watch the whole process in the video