Regions of Electromagnetic Radiation

Although this book is concerned only with the infrared region of the electromagnetic spectrum, it will be useful to look at the entire spectrum normally used in analysis. The spectrum is divided into several regions, each of which is used for a different purpose, and each of which furnishes a different type of information. These are the X-ray, ultraviolet, visible, near-infrared, infrared, far-infrared, and microwave regions. This division of the spectrum is arbitrary, and the boundaries 

Near-infrared region (long-wavelength electronic spectra and vibrational-rotational spectra) 

In practice there is some overlap among these regions, and depending on the instrumentation available it is frequently possible to go some distance beyond the usual boundary into the next region. In the laboratory it is possible to find instruments for use in each region, but in some cases the same instrument will cover two or three regions the usual instrument of the latter variety is the ultraviolet, visible, and near-infrared combination. 

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As the twentieth century proceeded, and modem technology for the detection and analysis of the light output from pyrotechnics and other light-emitting articles continued to improve, interest on the military side moved from the visible into the infrared region of electromagnetic radiation. 

The photomultiplier is a very versatile and sensitive detector of radiant energy in the UV, visible and NIR regions of electromagnetic radiation. The basic radiation... 

Wliile stars shine from the fusion of plain hydrogen, that reaction is unsuitable for nse on the earth. In substellar sizes the energy released leaves the reacting region as electromagnetic radiation much too quickly. 

Problem 14.13 Calculate the energy range of electromagnetic radiation in the UV region of the spectrum from 200 to 400 nm. How does this value compare with the values calculated previously for IR and NMR spectroscopy ... 

Chemiluminescence (CL) is defined as the emission of electromagnetic radiation (usually in the visible or near-infrared region) produced by a chemical reaction. 

Emission of electromagnetic radiation in the visible and ultraviolet regions of the spectrum by atoms and ions after electronic excitation in electrical discharges. 

The absorption of electromagnetic radiation by molecular species in solution in the UV/visible region is followed by relaxation from excited electronic states to the ground state mostly by a combination of radiationless processes. Vibrational relaxation, where the excess energy is rapidly dis-... 

Absorption of electromagnetic radiation in the infrared region of the spectrum resulting in changes in the vibrational energy of molecules. 

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