Kinetic energy dependence of ion-molecule reactions: Guided ion beams and threshold measurements

Over the past 20 years, ion beam methods have become a reliable experimental tool for the determination of thermochemical data. Confidence in these methods has required the synergistic development of improved instrumentation and enhanced analysis techniques. Guided ion beams, as introduced by Teloy and Gerlich in 1974 [Chem. Phys. 4 (1974) 417], have revolutionized our ability to measure accurate integral cross sections of ion-molecule reactions throughout the energy range of chemical interest. Such high quality data have then necessitated empirical and theoretical advances in our understanding of the kinetic energy dependence of chemical reactions. This need has led to increasingly sophisticated models that permit the extraction of meaningful thermodynamic values from the analysis of kinetic energy dependent data. Key contributions in the development of both advances are reviewed here. (C) 2000 Elsevier Science B.V.