Applications in atomic and molecular physics

Probably the most extensive area of application of quadrupole mass spectrometry has been that of atomic and molecular physics: it was for this market that the commercial instruments were first introduced and the variety of investigations which have consequently been made possible provides an obvious basis for illustrating the unique features possessed by the mass filter. The account which follows is divided into two main sections. The first deals with general applications of the quadrupole, in which the instrument is used essentially as an analyser for neutral or ionic species, e.g. the monitoring of residual gases and reaction products. The fields of vacuum technology, surface studies and gas phase studies are considered in turn. The second section is devoted to an account of the special applications of quadrupole fields in which use is made of properties such as ion containment. (Auth.)