Vibrational Spectroscopy for the Analysis of Geological and Inorganic Materials
Published Online: 15 SEP 2006
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Busca, G. and Resini, C. 2006. Vibrational Spectroscopy for the Analysis of Geological and Inorganic Materials. Encyclopedia of Analytical Chemistry.
- Published Online: 15 SEP 2006
The vibrational spectroscopies are those producing the entire (or part) vibrational spectrum of a sample, i.e. the collection of transition energies between its vibrational states. The simplest way to cause vibrational excitation is to allow the chemical species in its vibrational ground state to absorb an energy quantum from electromagnetic radiation of an appropriate energy, i.e. in the medium infrared (IR) or in the far infrared (FIR) regions. Transmission–absorption IR spectroscopy comprises the analysis of the quanta that are actually absorbed by a polyatomic chemical species and those that are not absorbed (so are transmitted). Other IR techniques relate to the analysis of the radiation that is emitted, diffused, or reflected by the sample. Another way to obtain part or all of the vibrational spectrum of a chemical species is to look at the inelastic scattering of beams other than IR radiation. Raman spectrometry is the analysis of the ultraviolet (UV), visible or near infrared (NIR) radiation that is scattered inelastically by the sample. Inelastic neutron scattering (INS) is the analysis of the energy of formerly monochromatic neutron beams after inelastic scattering by the sample. Analyses of the number and energies of the vibrational transitions of the sample, detected by each technique, yield information on the geometric (molecular and crystallographic) structure of the sample and on the strength and nature of the chemical bonds it contains.