The Structure of Small Molecules and Ions

The workshop on "The structure of small molecules and ions" was held at the Neve-Han guest house, near Jerusalem, Israel on December 13 to 18 in mem­ ory of the late Professor Itzhak Plesser. Professor Plesser played a central role in the research done both at the Weizmann Institute and at Argonne National Laboratories on the "Coulomb explosion" method. His friends honored his memory by organizing a meeting in which subjects related to Plesser's interests would be discussed. Just a week be­ fore the conference started we were struck by another tragedy -the death of our graduate student Ms. Hana Kovner, who participated in many of the Coulomb explosion experiments at the Weizmann Institute. We would like to dedicate these proceedings to her memory as well. The goal of the workshop was to bring together chemists and physicists working on different aspects of the structural problems of small molecular en­ tities. The time seemed appropriate for discussing experimental and theoretical concepts, since in recent years new methods have been introduced, and a large amount of information has been accumulated on systems not studied before, like unstable molecules, ions, van der Waals molecules and clusters. The program of the workshop reflects, we believe, these new developments. The meeting was characterized by intensive discussions in which the weak­ nesses and strengths of new and of well established concepts were revealed. We hope that it measured up to the high standards Itzhak Plesser maintained all through his scientific life.

Table of Contents:
Small Molecules and Ions: a Thing or Two We Still don’t Understand.- Vibrational Dynamics of Molecules — Theory.- Approximate Separability and Choice of Coordinates for Excited Vibrations of Polyatomic Molecules and Clusters.- The Application of Spectral Measures to the Stimulated Emission Pumping of Acetylene.- Dynamic Effects in the “Phase Change” Behavior of Small Clusters.- Structure of van der Waals Molecules.- Spectroscopic Signatures of Floppiness in Molecular Complexes.- Nonstatistical Behavior in the Vibrational Predissociation Dynamics of Binary and Tertiary Complexes.- Rovibrational Spectroscopy of ArCO Van der Waals Complex.- Structure of Ions.- Infrared Spectroscopy of Molecular Ions.- Estimation of Microwave and Infrared Spectral Parameters of Some Molecular Ions from Ab-initio Electronic Structure Calculations.- Photodissociation Dynamics of the H3+ Molecule.- Structure of Small Molecules via the Coulomb Explosion Method.- Preparation of Molecules in a Single State for Coulomb Explosion Measurements.- What Can Coulomb Explosions Teach Us About Clusters?.- Probing of Nuclear Waves in 3H2 (n=3).- Photoicnizatign and Photodetechment.- Multiphoton Ionization of Clusters: Reactions and Spectroscopy.- Photodetachment Spectroscopy of Negative Cluster Ions.- The Structure of Small Molecules and Ions as Determined by Photoionization Mass Spectroscopy.- Dynamic Aspect of Excited-State Photoelectron Spectroscopy. Some Small Molecules.- Probing Molecular Dynamics with Laser Photoelectron Spectroscopy.- A Photoion-Photoelectron Coincidence Study of (CO)2.- Electronic Structure-Theory.- Direct Calculation of Molecular Transition Energies by the Open-Shell Coupled-Cluster Method.- Topology of the Ground-State Surface of CH+4.- Fragmentation Mechanisms forMultiply-Charged Cations.- The Natural Bond Orbital Lewis Structure Concept for Molecules, Radicals, and Radical Ions.- Studies in the Paired Orbital Method III. The Structure of the PO Wavefunction.- Participation of a Hydrogen-Bridged Intermediate Ion [O=C(H)-H·CO]+ in the Loss of CO fron Ionized Glyoxal?.- Strucutre of Ions Via Mass-Spectrometry.- Studies of Ion Cluster Structures by MS/MS Methods.- Nonadiabatic Effects in Unimolecular Reactions of Ionized Molecules.- Potential Energy Surfaces and Dissociation Mechanisms of the C2H+4 Ion.- The Unimolecular Chemistry of [1, 2-Propanediol]+.: A Rationale in Terms of Hydrogen-Bridged Radical Cations.- The Energetic and Structural Insterpretation of Ion Photodissociation Spectra.- The Search for Novel Small Molecules and Radicals.- Structure Via Electric Spectroscopy.- New Information on the Structure and Dynamics of Molecular Cations from Experiments on the Spectroscopy of Polyatomic Rydberg States.- Production and Relaxation of Negative Cluster Ions by Use of High-Rydberg Rare Gas Atoms.- Excitation and Ionization of High n H-Atoms by Monochromatic and Bichromatic Microwave Fields.- Zero-Order Electronic Structure Model for Ionic Diatomic Molecules.- Recent Developments in Studies of Open-Shell Cations via Their Electronic Transitions.- Participants.