Brief introduction of X-ray diffraction

X-ray diffraction is a principle method to study phase and crystal structure of matter,when a certain substance is analyzed by diffraction, the substance is irradiated by X-ray to produce diffraction phenomena of different degrees,material composition, crystal type, intramolecular bonding mode, molecular configuration, conformation and other material characteristics determine the specific diffraction pattern of the substance.XRD technology has the advantages of no damage to the sample, no pollution, fast, high measurement accuracy, and can obtain a lot of information about crystal integrity,so,as a modern science technology of material structure and component analyse,XRD has been widely applied in the research and production of various disciplines.

When a monochromatic X-ray irradiate on a crystal, because the crystal is composed of a cell of atoms regularly arranged, the distance between these regularly arranged atoms is the same order of magnitude as the wavelength of the incident X-ray, so the X-rays scattered by different atoms interfere with each other, resulting in strong X-ray diffraction in some special directions,the orientation and intensity of the spatial distribution of the diffraction line are closely related to the crystal structure,according to its principle, the diffraction pattern of a crystal mainly has two characteristics: the spatial distribution of the diffraction line and the intensity of the diffraction beam, the distribution of the diffraction line is determined by the size, shape and orientation of the cell, and the intensity of the diffraction line depends on the type of atoms and their position in the cell, so different crystals have different diffraction patterns.