Foreword

This special issue of the International Journal of Quantum Chemistry celebrates two events-the 25th anniversary of the Theoretical Section of the Danish Chemical Society and the 60th birthday of Professor Jens Peder Dahl. As Professor Ballhausen points out in his overture, the two events are linked, since Jens Peder was one of the eight founders of the Theoretical Section. He served as the Section’s first chairman, and during more than a quarter of a century, he has been one of the leading figures in Danish theoretical chemistry. The manuscripts in this special issue were pre- sented at a symposium on “The Chemical Bond,” held in Copenhagen July 27-29, 1994. The invited speakers included Professors Per-Olov Lowdin, Stuart Rice, Clemens Roothaan, Yngve Ohm, Brian Sutcliffe, Joshua Jortner, Osvaldo Goscinski, Steve Berry, Pekka Pyykko, Jean-Louis Calais, Bob O’Connell, Elliott Lieb, Tom Ziegler, Xuejun Feng, Per Skancke, and Michael Springborg. I think that both the Theoretical Section and Jens Peder can be proud of having such friends as these! These were

International Journal of Quantum Chemistry, Vol. 58, 537 (1996) 0 1996 John Wiley & Sons, Inc.

many Danish quantum chemists whom it would have been appropriate to invite to contribute-so many, in fact, that the organizing committee (Gert Billing, Sten Rettrup, Niels Engholm Henriksen, and myself) decided that the only fair way to limit the number of lectures to the available time would be to have only non-Danish plenary speakers. (We counted Jan Linderberg as a Dane, Tom Ziegler as a Canadian, and Michael Springborg as a Bavarian!) The organizing committee is extremely grateful to all of the distinguished quantum chemists who participated in the symposium. We would also like to thank the Carlsberg Foundation and the Danish Scientific Research Council for their generous fi- nancial support. Finally, we would like to thank the International lournu2 of Quantum Chemistry for the opportunity to publish the proceedings of the symposium.

JOHN AVERY Guest Editor

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