In an XRD pattern, "a.u." stands for arbitrary units. It is a relative unit that indicates the relative intensity of a particular peak in the pattern.
The intensity of a peak in an XRD pattern is measured by the number of counts recorded by the detector for that particular peak. This count is then normalized with respect to the strongest peak in the pattern, which is assigned an intensity value of 100.
Arbitrary units are used in XRD pattern intensity measurement because the absolute intensity of a peak can vary depending on factors such as sample preparation and instrument settings. Using arbitrary units allows for a more standardized and relative measurement of peak intensities.
No, the intensity units in an XRD pattern cannot be converted to absolute units. As mentioned before, the absolute intensity of a peak can vary depending on various factors, making it difficult to determine an accurate conversion factor.
The intensity units in an XRD pattern can be compared between different patterns by looking at the relative intensities of the peaks within each pattern. The strongest peak in each pattern is assigned an intensity value of 100, and all other peaks are normalized accordingly. This allows for a relative comparison of peak intensities between different patterns.