The need for accurate computational procedures to evaluate detailed properties of gas phase chemical reactions is evident when one considers the wealth of information provided by laser, molecular beam and fast How experiments. By stressing ordinary scalar computers to their limiting performance quantum chemistry codes can already provide sufficiently accurate estimates of the stability of several small molecules and of the reactivity of a few elementary processes. However, the accurate characterization of a reactive process, even for small systems, is so demanding in terms of computer resources to make the use of supercomputers having vector and parallel features unavoidable. Sometimes to take full advantage from these features all is needed is a restructure of those parts of the computer code which perform vector and matrix manipulations and a parallel execution of its independent tasks. More often, a deeper restructure has to be carried out. This may involve the problem of choosing a suitable computational strategy or the more radical alternative of changing the theoretical treatment. There are cases, in fact, where theoretical approaches found to be inefficient on a scalar computer exhibit their full computational strength on a supercomputer.

This book highlights recent progress in the chemistry of radicals. Developments include the growing use of lasers to generate radicals, the application of lasers to provide state, angular, polarization, energy and real-time resolution in kinetics and dynamics experiments, the development of theories for handling the reactions of radicals, and the simulation of the reaction dynamics of increasingly larger systems for direct comparison to experimental results. The book emphasizes the increasing interaction between experimental dynamics, kinetics and theory. It is appropriate for chemistry graduate students and researchers about to enter the field. However, the discussions of some topics progress to a more advanced level so that even an expert will find the book useful.

Covers both molecular and reaction dynamics. The work presents important theroetical and computational approaches to the study of energy transfer within and between molecules, discussing the application of these approaches to problems of experimental interest. It also describes time-dependent and time-independent methods, variational and perturbative techniques, iterative and direct approaches, and methods based upon the use of physical grids of finite sets of basic function.

The IEEE Third International Conference on Algorithms and Architectures for Parallel Processing (ICA3PP-97) will be held in Melbourne, Australia from December 8th to 12th, 1997. The purpose of this important conference is to bring together developers and researchers from universities, industry and government to advance science and technology in distributed and parallel systems and processing.

Molecular Physics and Hypersonic Flows bridges the gap between the fluid dynamics and molecular physics communities, emphasizing the role played by elementary processes in hypersonic flows. In particular, the work is primarily dedicated to filling the gap between microscopic and macroscopic treatments of the source terms to be inserted in the fluid dynamics codes. The first part of the book describes the molecular dynamics of elementary processes both in the gas phase and in the interaction with surfaces by using quantum mechanical and phenomenological approaches. A second group of contributions describes thermodynamics and transport properties of air components, with special attention to the transport of internal energy. A series of papers is devoted to the experimental and theoretical study of the flow of partially ionized gases. Subsequent contributions treat modern computational techniques for 3-D hypersonic flow. Non-equilibrium vibrational kinetics are then described, together with the coupling of vibration-dissociation processes as they affect hypersonic flows. Special emphasis is given to the interfacing of non-equilibrium models with computational fluid dynamics methods. Finally, the last part of the book deals with the application of direct Monte Carlo methods in describing rarefied flows.

"Proceedings of the Ninth International Conference on Computing Methods in Applied Sciences and Engineering, Paris, France, January 29-February 2, 1990"--T.p. verso.

The latest volume in the highly acclaimed series addresses atomic collisions, assessing the status of the current knowledge, identifying deficiencies, and exploring ways to improve the quality of cross-section data.Eleven articles, written by foremost experts, focus on cross-section determination by experiment or theory, on needs in selected applications, and on efforts toward the compilation and dissemination of data. This is the first volume edited under the additional direction of Herbert Walther. Presents absolute cross sections for atomic collisions Uses benchmark measurements and benchmark calculations Discusses needs for cross-section data in applications Contains a guide to data resources, bibliographies, and compendia

The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics.

This volume focuses on molecular clusters, bound by van der Waals interactions and hydrogen bonds. Twelve chapters review a wide range of recent theoretical and experimental advances in the areas of cluster vibrations, spectroscopy, and reaction dynamics. The authors are leading experts, who have made significant contributions to these topics.The first chapter describes exciting results and new insights in the solvent effects on the short-time photo fragmentation dynamics of small molecules, obtained by combining heteroclusters with femtosecond laser excitation. The second is on theoretical work on effects of single solvent (argon) atom on the photodissociation dynamics of the solute H2O molecule. The next two chapters cover experimental and theoretical aspects of the energetics and vibrations of small clusters. Chapter 5 describes diffusion quantum Monte Carlo calculations and non additive three-body potential terms in molecular clusters. The next six chapters deal with hydrogen-bonded clusters, reflecting the ubiquity and importance of hydrogen-bonded networks. The final chapter provides the microscopic theory of the dynamics and spectroscopy of doped helium cluster, highly quantum systems whose unusual properties have been studied extensively in the past couple of years.