Quantum mechanical calculations in physics, chemistry and biology are widely recognized as useful interpretative and predictive tools. Unfortunately, they are plagued by unfavorable convergence limitations due to the use of finite linear combinations of basis functions. With the current computer technologies, there is a possible way out to the situation by solving numerically the corresponding wave equations. The present interest and need for numerical determination of electronic structure of atoms, diatomic and poly atomic molecules led us to organize a NATO-ARW devoted to these questions. The aim of the meeting was to provide a review of the state of the art about techniques and applications. The organizing committee consisted of Drs. G. Berthier, P. Claverie, M. Defranceschi, J. Delhalle, H.J. Monkhorst and P. Pyykk6. It was a great sorrow for us to be informed in January 88 of the death of Professor P. Claverie who supported so enthusiastically the idea of having such a meeting organized. The NATO Advanced Research Worshop on : " Numerical Determination of the Electronic Structure of Atoms, Diatomic and Poly atomic Molecules" was held at Versailles (France) from April 17th till April 22th, 1988.

The NATO Advanced Study Institute on "Electronic Structure and Properties of Polymers" was held at the Facultes Universitaires de Namur (F.U.N.) from August 31 till September 14, 1977. We wish to express our deepest gratitude to the Scientific Affairs Division of NATO, the main sponsor of this Institute, and to the Facultes Universitaires Notre Dame de la Paix and their Board who gave us generous financial help as well as accommodation for the School. Our sincere thanks to Dr Tilo Kester from the NATO Scien tific Affairs Division and Prof. Roger Troisfontaines, Rector and President f the Facultes Notre Dame de la Paix. This volume contains the main lectures of the Institute. It is our great pleasure to thank all the lecturers for their most excellent and interesting lectures and for the clarity of their manuscripts. During the School the participants and lecturers felt that though there has been considerable progress in recent years in the methods applicable to the quantum theoretical treatment of polymers, not very many calculations of their properties have been performed. This is the reason that the title of this volume has been changed to "Quantum Theory of Polymers.""

Quantum mechanical calculations in physics, chemistry and biology are widely recognized as useful interpretative and predictive tools. Unfortunately, they are plagued by unfavorable convergence limitations due to the use of finite linear combinations of basis functions. With the current computer technologies, there is a possible way out to the situation by solving numerically the corresponding wave equations. The present interest and need for numerical determination of electronic structure of atoms, diatomic and poly atomic molecules led us to organize a NATO-ARW devoted to these questions. The aim of the meeting was to provide a review of the state of the art about techniques and applications. The organizing committee consisted of Drs. G. Berthier, P. Claverie, M. Defranceschi, J. Delhalle, H.J. Monkhorst and P. Pyykk6. It was a great sorrow for us to be informed in January 88 of the death of Professor P. Claverie who supported so enthusiastically the idea of having such a meeting organized. The NATO Advanced Research Worshop on : " Numerical Determination of the Electronic Structure of Atoms, Diatomic and Poly atomic Molecules" was held at Versailles (France) from April 17th till April 22th, 1988.