Introduction

Abstract

Infra-red spectroscopy is widely employed in commerce and in organic chemistry for the recognition and the quantitative analysis of structural units in unknown compounds. Almost all the spectrometers employed in industry are used for this purpose, although, in the hands of theoretical physicists, the spectra can also be used to obtain fundamental data on the mechanics of simple molecules. The latter studies are extremely useful to the analyst, in that the particular motions associated with the various characteristic frequencies are determined, so that it is possible to assess to some extent the likelihood of frequency shifts occurring with changes in the local environment of the group. Nevertheless, these studies are necessarily restricted to simple molecules in which the frequencies associated with various structural units are often out of line with those found for more complex materials.