FIGURE 2. X-ray diffraction patterns of two CdSe rod-shaped nanocrystals.
From the following article:
Shape control of CdSe nanocrystals
Xiaogang Peng, Liberato Manna, Weidong Yang, Juanita Wickham, Erik Scher, Andreas Kadavanich and A. P. Alivisatos
Nature 404, 59-61(2 March 2000)
doi:10.1038/35003535
These two nanocrystals have the same short-axis dimension (within experimental error). The sizes and aspect ratios were found from the experimental patterns by the simulations shown.