Tunnelling in molecular spectra

Abstract

There are many features of molecular spectra which can only be explained by the same concepts as those on which the treatment of tunnelling problems is based, such as the uncertainty principle. Although it would be usually misleading to say that these features are ‘caused’ by tunnelling processes, they are sufficiently closely related to chemical reactions to merit a chapter in this book. There exists a vast literature on both the theoretical and the chemical aspects of this subject, and in many instances the complete picture is embellished with so much detail that it may well look rather obscure to the non-spectroscopic layman. No attempt will therefore be made either to cover the field completely or to deal adequately with spectroscopic niceties. Instead a simplified account will be given of a few selected topics which bear a fairly close analogy to chemical processes.