Dynamics In Dissociative Recombination

Dissociative Recombination of Molecular Ions with Electrons is a comprehensive collection of refereed papers describing the latest developments in dissociative recombination research. The papers are written by the leading researchers in the field. The topics covered include the use of microwave afterglows, merged beams and storage rings to measure rate coefficients and to identify the products and their yields. The molecules studied range in size from the smallest, H2+, to bovine insulin ions. The theoretical papers cover the important role of Rydberg states and the use of wave packets and quantum defect theory to deduce cross sections, rate constants and quantum yields. Several theoretical and experimental papers address the controversial topic of H3+ dissociative recombination and its importance in the interstellar medium. Dissociative recombination studies of other molecular ions in the interstellar medium and in cometary and planetary atmospheres are covered. Ionization is an important competitive process to dissociative recombination and its competition with predissociation and its role in the reverse process of the association of neutral species is presented. Dissociative attachment, in which an electron attaches to a neutral molecule, has many similarities to dissociative recombination. The topics covered include the accurate calculation of electron affinities, attachment to molecules, clusters, and to species absorbed on solid surfaces and electron scattering by a molecular anion.

Advances made in the study of the dissociation dynamics and product branching ratios of energized transient neutral molecules formed by charge-transfer (DCE) and recombination of cations with free electrons (DR) are reviewed. The results obtained include detailed measurements of the three-body dissociation of H3, O4 and sym-triazine (HCN)3, as well as the product branching ratios for the two-body dissociation of CM5+ and M30+. These results have significance for a number of Air Force applications, one including ion-assisted ignition and combustion for hypersonic vehicle applications. This project aimed to extend our knowledge of the fate of transient neutrals produced in plasma environments while providing fundamental new information on the dynamics of two- and three-body dissociation processes. As noted below, significant successes in the study of DCE processes were achieved, while the efforts at carrying out DR measurements on the last-ion-beam apparatus were not successful.

Dissociative recombination (DR) of molecular ions with electrons is a complex, poorly understood molecular process. Its critical role as a neutralising agent in the Earth's upper atmosphere is now well established and its occurrence in many natural and laboratory-produced plasma has been a strong motivation for studying the event. In this book theoretical concepts, experimental methodology and applications are united, revealing the governing principles behind the gas-phase reaction. The book takes the reader through the intellectual challenges posed, describing in detail dissociation mechanisms, dynamics, diatomic and polyatomic ions and related processes, including dissociative excitation, ion pair formation and photodissociation. With the final chapter dedicated to applications in astrophysics, atmospheric science, plasma physics and fusion research, this is a focused, definitive guide to a fundamental molecular process. The book will appeal to academics within physics, physical chemistry and related sciences.

Proceedings of a NATO ARW held in Saint Jacut de la Mer, Brittany, France, May 3-8, 1992

Dissociative recombination is a complex molecular process that occurs in any plasma cold enough to contain molecular constituents. It is the dominant recombination process in planetary ionospheres and interstellar clouds. In this book, recent developments in the fields of molecular ion physics, atomic and molecular theory, astrochemistry, aeronomy and plasma physics are discussed.

In this book, the latest developments in the study of the dissociative recombination of electrons and molecular ions are discussed. This process is of great importance in controlling the physical and chemical states of ionized gases. It has direct application to astrophysics, aeronomy, thermonuclear fusion research, plasma processing and combustion science.

Using the CRYRing Facility in Stockholm Coupled with an MCP-CCD detector, and a differential stopping foil, we have determined dynamic parameters in the three-body dissociative recombination of H2O+. These include the distribution between the O(3P) and O(1D) channels, the distribution of H atom recoil energies in the O(3P) channel and the distribution of angles between the two departing H atoms.