Influence of surface relaxations on X-ray intensities of microcrystals

The influence of surface relaxations on the intensity of microcrystals was investigated. Since the volume fraction of near surface atoms becomes appreciable for submicrometer crystals, it is important to estimate whether observed intensities of submicrometer crystals can be interpreted with standard structure refinement methods or whether surface relaxations produce a significant deviation from the intensities of the perfect crystal. Structure simulation techniques were applied in order to calculate the intensity of microcrystals of various sizes. Different models of surface relaxations were applied. Structure refinements on the data sets calculated for these models showed that submicrometer crystals down to 0.5 μm in diameter are not affected by surface relaxations. Smaller crystals below 0.1 μm in diameter are significantly affected by surface relaxations. Great care will have to be taken when refining observed intensities of these small crystals.