I believe that X-ray crystallography, the study of atomic crystals is based on x-ray diffraction - the wave phenomena which allows such analysis to be possible.
X-ray crystallography is a technique in crystallography in which the diffraction pattern of maxima and minima which is produced by the diffraction of X-rays through the closely spaced lattice of atoms in a crystal is recorded on photographic paper and then analyzed to reveal the nature of that lattice.