The present volume contains the text of the invited lectures presented at the Symposium on Many Body Methods in Quantum Chemistry, held on the campus of Tel Aviv University in August 1988. The Symposium was a satellite meeting of the Sixth International Congress on Quantum Chemistry held in Jerusalem. The development and application of many-body methods in Quantum chemistry have been on the rise for a number of years. This is therefore a good time for an interim report on the state of the field. It is hoped that such a report is hereby provided, though it may not be complete. The Symposium was held under the auspices of Tel Aviv University, Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry. Other sponsors were the Israeli Academy of Sciences and Humanities, and the Israeli Ministry of Science and Development. Many thanks go to all of them. Finally, I would like to thank all the speakers and participants for making the meeting the enjoyable and (I hope) profitable experience it was. Tel Aviv, Israel Uzi Kaldor TESTS AND APPLICATIONS OF COMPLETE MODEL SPACE QUASIDEGENERATE MANY-BODY PERTURBATION THEORY FOR MOLECULES Karl F. Freed The James Franck Institute and Department of Chemistry The University of Chicago, Chicago, DUnois 60637 U.S.A.

Perturbation-Theory Methods

Tests and Applications of Complete Model Space Quasidegenerate Many-Body Perturbation Theory for Molecules
Diagrammatic Approach to the Calculation of the Lower Bounds Using Optimized Inner Projection Technique. Application to the Cyclic Polyene Model
Multi-Reference-State Rayleigh-Schrödinger Perturbation Theory
Many-Body Theory of Van der Waals Interactions
Partitioning of the Vibrational-Electronic Hamiltonian. Ab Initio Correlated Calculations of the First Vibronic Transitions for Some Simple Molecules.
Coupled Cluster Methods
Some Consideration of Alternative Ansätze in Coupled-Cluster Theory
Spin-Adapted Multi-Reference Coupled Cluster Formalism Including Non-Linear Terms and its Application to the H4 Model System
On the Construction of Size-Extensive Effective Hamiltonians for Time-Independent and Time-Dependent Quasi-Degenerate Systems
Atomic and Molecular Applications of the Multireference Coupled-Cluster Method
Quadratic Configuration Interaction
Quadratic Configuration Interaction Method: Recent Applications and Comparison with Other Correlation Techniques
Propagator Methods
On the Connection between Effective Hamiltonians and Propagators
An Effective Liouvillean Formalism for Propagators in Fock Space: Connection with Effective Hamiltonian Approach for Energy Differences
Development of Multiconfigurational Green's Function Approaches
Relativistic Many-Body Theory
A Relativistic Coupled-Cluster Approach with Radiative Corrections
On the Relativistic Many-Body Perturbation Theory of Atomic and Molecular Electronic Structure
List of Participants.