By observing how light bounces, scatters, is emitted, or is absorbed, scientists can tell a lot about the specific material. X-ray spectroscopy specifically refers to looking at the light in the X-ray portion of the electromagnetic radiation spectrum to gather information about various forms of matter. X-rays have wavelengths of 0.01-10 nanometers and a frequency in the range of 30 petahertz to 30 exahertz. These specific wave properties allow X-rays to penetrate through various objects. X-rays are most commonly associated with medical X-ray scans which allow radiologists to see the bones of a patient without having to cut into them.

In X-ray spectroscopy, the sample is struck with high-energy particles resulting in the material emitting X-rays. When they are hit by these high-energy particles, the individual atom’s electrons transition, either gaining energy or losing energy, which then results in them emitting X-ray photons. These emitted photons possess properties that are characteristically unique to the materials that they are emitted from. By comparing a sample’s spectral data with that of a known substance, detailed information about the sample can then be obtained. This excitation can be triggered by electrons, other high-energy charged particles, or beams of X-rays. There are different techniques within X-ray spectroscopy that test for specific properties, use specific types of equipment, and are made to test for specific types of materials. Most techniques, however, involve analyzing how the material disperses radiation to determine aspects of its atomic structure and elemental makeup.