This volume is the outgrowth of a workshop held in October, 2000 at the Institute for Theoretical Atomic and Molecular Physics at the Harvard- Smithsonian Center for Astrophysics in Cambridge, MA. The aim of this book (similar in theme to the workshop) is to present an overview of new directions in antimatter physics and chemistry research. The emphasis is on positron and positronium interactions both with themselves and with ordinary matter. The timeliness of this subject comes from several considerations. New concepts for intense positron sources and the development of positron accumulators and trap-based positron beams provide qualitatively new experimental capabilities. On the theoretical side, the ability to model complex systems and complex processes has increased dramatically in recent years, due in part to progress in computational physics. There are presently an intriguing variety of phenomena that await theoretical explanation. It is virtually assured that the new experimental capabilities in this area will lead to a rapid expansion of this list. This book is organized into four sections: The first section discusses potential new experimental capabilities and the uses and the progress that might be made with them. The second section discusses topics involving antihydrogen and many-body phenomena, including Bose condensation of positronium atoms and positron interactions with materials. The final two sections treat a range of topics involving positron and positronium interactions with atoms and molecules.

Inhalt
Positron Sources and Beams.- A Laser-cooled Positron Plasma.- Trap-based Positron Beams.- Intense Radioisotope Sources for Spin Polarized Positron Beams.- Antihydrogen, Bose-condensed Positronium, and Positrons in Materials.- Collisions of H and ¯H.- Positron Physics in a New Perspective.- The Bose-einstein Condensation of Positronium in Submicron Cavities.- Cooling and Quenching of Positronium in Porous Material.- New Experiments with Bright Positron and Positronium Beams.- Positron States in Materials: Dft and QMC Studies.- Depth-profiled Positron Annihilation Spectroscopy of Thin Insulation Films.- Positron and Positronium Interactions with Atoms.- The Scattering of Positrons and Positronium by Atomic Targets.- Positronic Atoms.- Perspectives on Physics with Low Energy Positrons: Fundamentals, Beams and Scattering.- Positron Chemistry by Quantum Monte Carlo.- Antimatter Compounds.- Positronium-atom/Molecule interactions: Momentum-Transfer Cross Sections and Zeff.- Correlations between Cross Sections and Threshold Energies for Positronium Formation and Direct Ionization.- Positron and Positronium Interactions with Molecules.- Scattering of Positronium Atom off Atomic Hydrogen and Helium Targets.- Atomic and Molecular Physics Using Positron Traps and Trap-Based Beams.- Experimental Studies of Positron Scattering Using a Weak Radioactive Isotope.- Future Opportunities for Positronatom (Molecule) Scattering.- Theory of Positron Annihilation on Molecules.- Bound States of Positron with Molecules.- Low-energy Positron Dynamics in Polyatomic Gases.- A Test Calculation on SF6 of Model Potentials for Correlation and Polarization Effects in Positron Scattering from Molecules.- On the Contribution of Polarization - Correlation Forces to High Annihilation Rates inPositronmolecule Collisions.