Atomic Emission Spectroscopy
In principle, emission spectroscopy can be applied to both atoms and molecules. Molecular infrared emission, or blackbody radiation played an important role in the early development of quantum mechanics and has been used for the analysis of hot gases generated by flames and rocket exhausts. Although the availability of FT–IR instrumentation extended the application of IR emission spectroscopy to a wider array of samples, its applications remain limited. For this reason IR emission is not considered further in this text. Molecular UV/Vis emission spectroscopy is of little importance since the thermal energies needed for excitation generally result in the sample’s decomposition.
The focus of this section is the emission of ultraviolet and visible radiation fol- lowing thermal or electrical excitation of atoms. Atomic emission spectroscopy has a long history. Qualitative applications based on the color of flames were used in the smelting of ores as early as 1550 and were more fully developed around 1830 with the observation of atomic spectra generated by flame emission and spark emis sion. Quantitative applications based on the atomic emission from electrical sparks were developed by Norman Lockyer (1836–1920) in the early 1870s, and quantitative applications based on flame emission were pioneered by H. G. Lunde- gardh in 1930. Atomic emission based on emission from a plasma was introduced in 1964.
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