16 May

Spectroscopy

Spectroscopy is the study of how radiated energy interacts with matter.  Spectroscopy started with UV & Vis spectroscopy (Ultraviolet and visible light), then infrared; now most parts of the electromagnetic spectrum are passed through matter to study the interactions.  Atoms and molecules have specific responses to radiated energy which is used to identify and quantify them.  In atomic spectroscopy the elements are burned in a flame or plasma, the color emitted not only identifies them but quantifies them.  This is how we know what a star is made of, by it’s characteristic emission lines.  In UV/Visible spectroscopy we are looking for absorption of certain wavelengths of light.  Different molecules absorb different wavelengths of visible and UV light in solution.  The amount of light absorbed is directly related to the concentration of the molecule.  In infrared spectroscopy the absorption of light a different frequencies indicates the structure of the molecule probed.  Raman spectroscopy, which is in the infrared, observes the scattered light rather than the absorbed light.  Raman scattering is a fingerprint of the specific molecules or mixture of molecules.  One application of Raman scattering is the identification of counterfeit pharmaceuticals.  X-Rays scattering techniques such as X-Ray diffraction are used to determine the crystallographic structure of materials among other properties.  Spectroscopy is performed with wavelengths from microwave to gamma radiation.

Robin Prymula