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The Science of Spectroscopy
Historically, spectroscopy has referred to the way in which objects such as prisms disperse visible light according to the wavelength of its constituents. These days, scientists use spectroscopic techniques in a variety of ways. For example, spectroscopy can be used analyze samples to determine their composition, or to examine the types of light which comes to us from space, and use that information to learn about the universe.
Spectroscopy machinery combines an energy sources with a device which measures energy changes. During a spectroscopic analysis, a sample is bombarded with energy from the source, and changes in the energy level of the source and the sample are recorded.
This works because atoms and molecules each have a very specific “fingerprint” of light emission and absorption, which change as they absorb or emit energy. By examining these patterns using machinery designed for the purpose, sample analysis can determine the composition and other characteristics of a given sample.
Under spectroscopic analysis, information about energy levels, molecular geometry, chemical bonds and interactions, and other chemical and biochemical measurements and processes can be obtained.
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Atomic spectroscopy examines the absorption and emission of radiation by free atoms, to produce line spectra, which can be analyzed to determine the quantity and quality of atoms in a given sample.
Within the category of atomic spectroscopy are further categories. Atomic spectroscopy can be characterized according to the type of spectroscopy used to collect data, or the atomization source used. Generally, either optical spectrometry or mass spectrometry is used to collect data.
Each method has its own specific advantages and drawbacks, however. In general, mass spectrometry gives more accurate results and higher performance, but at the cost of higher costs, and a higher risk of failure when performing an analysis. Optical spectrometry, on the other hand, is a simpler, less expensive process that is somewhat less accurate (but is still adequate for many purposes).
In Atomic Optical Spectrometry, light is passed through atoms, and absorption patterns of the light are analyzed. Light is absorbed by the atoms if the wavelength of that light has energy which corresponds to the energy difference between two different energy levels of the atoms in the sample.
Atomic Mass Spectrometry equipment includes an ion source, a detector, and an analyzer. The mass analyzer detects the atoms present in a sample by examining the ratio between the mass and the charge of each atom.