PREFACE

The Fourth International Symposium on Surface Physics organized by the Netherlands Vacuum Society (NEVAC) was held on June 23-25, 1976, in the Auditorium of the University of Technology, Eindhoven, The Netherlands. The Conference was sponsored by EPS, IUVSTA, KNCV and NNV (The Chemical and Physical Societies of the Netherlands). The Proceedings contain the six invited and thirty-six of the contributed papers presented to an audience of 230 participants from 17 countries.

The scope of the conference aimed at improving our understanding of the rela- tionships between the geometrical structure, the electronic properties and the chemical composition of surfaces. The six invited speakers demonstrated in their lec- tures the importance of such a better understanding and the progress made in this respect. Many contributed papers clearly emphasized this point, mainly by using such experimental techniques as UPS, LELS, LEED and ISS. Two important topics were the semiconductor surfaces of some III-V compounds and the reactivity of metal surfaces.

We are particularly grateful to the members of the paper selection committee A. Benninghoven (Miinster, Germany), J. Friedel (Orsay, France), O.S. Heavens

(York, UK) and J. van Laar (Eindhoven, The Netherlands). They carried out the selection of the contributed papers in an admirable way. Finally, we like to thank all those people that have contributed to this meeting, in particular the conference secretary J. Scheer, assisted by A. Kipperman and F. Meyer.

A.vanOOSTROM M.J.SPARNAAY