citw said:Very commonly in thin film articles/journals, I find the full width at half maximum of X-ray rocking curves associated with the quality (order) of the surface. For example, if the same material is grown on two different substrates, A and B, with FWHM values of 0.11° for A and 0.6° for B, why do we interpret the quality of the A film to be better than B? In other words, why does a lower FWHM indicate higher crystalline quality?
Full Width at Half Maximum (FWHM) is a measure used to describe the width of a peak in a graph or spectrum. It represents the width of the peak at half of its maximum height.
FWHM is calculated by finding the half-maximum points on either side of the peak and measuring the distance between them. This can be done using mathematical formulas or by visually estimating the points on a graph.
The FWHM value provides information about the width of a peak, which can be used to determine the resolution or precision of a measurement. A smaller FWHM indicates a narrower peak and therefore a higher resolution or precision.
The FWHM of a peak can be affected by various factors, such as the instrument used for measurement, the sample preparation method, and the type of data processing techniques applied. These factors can introduce noise or distortions in the measurement, leading to a broader peak and a higher FWHM value.
In various fields of science, FWHM is used as a quantitative measure to compare the resolution and precision of different instruments and methods. It is also used in data analysis and interpretation, such as in spectroscopy, chromatography, and crystallography, to determine the characteristics of a peak and make accurate measurements.