Of Volume 2.- 8. Flowing Afterglow Studies.- 1. Introduction.- 2. Studies Bearing on Intermediate Complex Formation in Thermal Energy Collisions.- 2.1. Temperature Dependence of Slow Ion-Molecule Reactions.- 2.2. Three-Body Reaction Rate Constants.- 2.3. Rotational Excitation in Ion-Neutral Reactions.- 2.4. Miscellaneous Considerations of Intermediate Complex Processes.- 3. Studies Bearing on Negative-Ion Resonance Formation.- 4. Studies Bearing on Energetics.- 5. Conclusions.- References.- 9. Ion Cyclotron Resonance Spectrometry.- 1. Introduction.- 1.1. General Characteristics.- 2. Theoretica.

After a few faint stirrings of interest in ion-molecule reactions during the early days of mass spectrometry, the subject was almost completely neglected for many years. There was a renascence of interest in the subject following pioneering experiments by Tal'roze in Russia and independently by Steven son and Schissler and Field, Franklin, and Lampe in this country. Since that time, interest in the subject has continued to grow and the number of papers published to expand almost exponentially during the past 15 years. The result is a body of literature that is now almost beyond any single individual's capacity for encompassing in his reading and research activities. Thus, it seemed timely to prepare a book giving in some detail a comprehen sive review of the field. Ideally, such a book would be written by one or possibly two authors. Unfortunately, the sheer bulk and variety of the studies of ion-molecule reactions has made it impractical for a single person to prepare a book on the subject in a time that would permit it to be issued before the material covered was obsolete. Consequently, the only practical, although surely not the ideal, solution is to issue a multiauthor volume. The present book represents our best efforts to accomplish this goal. We have secured from 18 authors material representing the most advanced work in the field and the resulting compilation is presented herein.

The investigation of the elementary reactions of reactive intermediate species began about half a centruy ago with the advent of free radical kinetics as an active area of chemical research. In spite of the relatively greater ease of detection of a species carrying an electrical charge, and the fact that organic chemists had for decades postulated mechanisms involving ionic intermediates, the systematic study of the elementary reactions of ions was delayed for more than twenty years after the first beginnings of free radical kinetics. Even at this writing, in 1978, the word "kinetics" is considered by many chemists to be synomomous with "kinetics of neutral species". Yet in spite of the relatively late start and separation from the mainstream of kinetics, the field of ion physics and chemistry is fluorishing, and growing at an ever faster pace. Instrumentalists devise ever more sophisticated apparatuses with capabilities of delving into nearly every aspect of the interactions between ions and molecules. Even satellites orbiting the earth are now being used effectively to determine rate coefficients of ionospheric ion-neutral reactions, some of which can not as yet be measured in the laboratory.

Chemical reactions between ions and neutral gas are very important in the interstellar medium, since they usually have much lower barriers than neutral-neutral reactions. Thus, they are more likely to take place at low temperatures. In this work, the endothermic reactions of CH2D+, H2D+, and N+ with H2 have been investigated in a temperature variable 22-pole ion trap. Under the chosen conditions inside the trap the chemical processes are comparable to those in typical astrophysical environments. At low temperatures, the reactions mentioned above depend very sensitively on the translational and internal energies of the reaction partners. This dependence can be utilized to gain information on the energy levels or the population of the internal states. Based on this sensitivity, two different types of investigations were performed in this work. High resolution spectra of CH2D+ were obtained, resulting in improved predictions for pure rotational transitions. First steps were made towards a detailed understanding of the processes in laser induced reactions, often leading to non-Gaussian line profiles. In addition, the influence of internal states on ion-molecule reactions allowed to determine the purity of para hydrogen samples and yielded insight into the reaction kinetics of the system N+ + H2.

This book explores the mechanism of alkali-metal ion/molecule association reaction, surveys the instrumental basis to study its kinetic, and describes the instrumentation to the measurement of alkali-metal ion affinities. The applications of the ion complexation mechanism in the condensed phase in reaction to direct analysis MS are also covered. Other topics include mechanism and reaction rate, experimental and theoretical ion affinities, applications of ion attachment reactions (IAR) to mass spectrometry such as alkali ion CIMS, ion attachment MS and cationization mass spectrometry of ESI, FAB, FD, LD, MALDI and SIMS and topics of IAR-based direct analysis mass spectrometry.

State-Selected and State-to-State Ion-Molecules Reaction Dynamics details the recent experimental and theoretical accomplishments in the field to date by some of its foremost researchers and theorists. Divided into two parts, each of which separately describe the experimental and theoretical aspects of the field, State-Selected and State-to-State Ion-Molecule Reaction Dynamics is an accessible, well organized look at a highly useful and emerging chemical specialty. Part 1, "Experiment," contains eight in-depth studies, which illustrate the key experimental work being done in the field today: Chapter 1 provide a comprehensive review of the theory and application of inhomogeneous rf fields for the study of the dynamics of low-energy ion-molecules processes Chapter 2 describes the application of multiphoton ionization (MPI) for the preparation of reactant ion states Chapter 3 reviews the application of MPI schemes for state specific cross-section measurements involving transition metal cations Chapter 4 describes the development of the threshold photoelectron secondary ion coincidence (TESICO) method Chapter 5 presents the conceptual and practical aspects of a multicoincidence technique Chapter 6 details the experimental results obtained using the photoionization and differential reactivity methods Chapter 7 reviews the several recent crossed beam studies of charge transfer and collision-induced dissociation systems involving atomic and molecular ions Chapter 8 is a survey of 15 years of high resolution crossed beam scattering of protons with atoms, diatoms, and poly-atomic molecules State-Selected and State-to-State Ion-Molecule Reaction Dynamics, Part 1: Experiment offers professionals a true state-of-the-science look at this fascinating and increasingly influential subject.