Spectroscopy

Abstract

Spectroscopy, the study of electromagnetic radiation and its interaction with matter as a function of frequency or wavelength, is a versatile and powerful tool for investigating atomic and molecular structure, as well as for qualitative and quantitative analysis. Optical spectroscopy is surveyed emphasizing its applicability for qualitative and quantitative laboratory and process analysis and for monitoring atmospheric pollutants. Absorption, emission (from excited samples, and radiometry of ambient thermal emission), scattering (elastic and Raman), and luminescence (fluorescence and phosphorescence) spectroscopies are discussed for the different regions of the electromagnetic spectrum: radio and microwaves, mid‐ and near‐infrared, molecular ultraviolet–visible absorption, atomic absorption and emission, X‐ray, and γ‐ray, in each case discussing instrumentation, sampling, and applications. Special techniques covered include null‐background detection, nonlinear Raman spectroscopy and other laser‐induced processes, optical activity, and Mössbauer spectroscopy. Modern ultrasensitive spectroscopies being developed for analytical use are briefly reviewed.