Shyama P. Sinha - Böcker

"Meditationis est perscrutari occulta; contemplationis est admirari perspicua . . . Admiratio generat qurestionem, qurestio investigationem, investigatio inventionem" once wrote HUGO DE S. VICTORE and possibly described best the life span of the rare earths since the Swedish Army Lieutenant, C. A. ARRHENIDS' discovery of an unusual black mineral at Ytterby in 1787. Since then the rare earths have passed through the machinery of various phases of physical science. Europium as a member of the rare earth family shows characteristics of the series as a whole as well as some typical behaviour of its own due to the presence of its six f electrons i. e. , one less than the half-filled shell. This present volume attempts to provide an understanding of the various aspects of its chemical and physical behaviour. In doing so, it is hoped to provide the reader with more than just a list of the complete bibliography on the subject, and I have tried to review the literature for it's interesting features, balancing the experimental facts with the help of the minimum amount of theory as far as possible. Experience has shown us that the trend of inorganic research has changed during the past years and one frequently needs some understanding of chemical spectroscopy and quantum mechanics to be able to appreciate the developments in this field and to interpret the wealth of experimental data. The reader is referred to B. G. WYBOURNE'S book: Spectroscopic Properties of Rare Earths (ref. [488]), and B. R.

Science is not a mere collection of facts. It is the correlation of facts, the interpretative synthesis of the available knowledge and its application that excite the imagination of a scientist. Even in these days of modern technology, the need for quick and accurate dissemination of new information and current concepts still exists. Conferences and Symposia offer one direct method of communication. The Summer Schools are another approach. The success of a Summer School is mainly due to that human factor and under­ standing that goes with it and allows for extensive and often time-unrestricted discussions. During the course of the past 20 years, one of the most in­ tensively studied groups of elements in the Periodic Table is the Lanthanides. In this period, we have increased our knowledge on these once exotic elements, which were once considered to be a part of a lean and hungry industry, many-fold due to the involve­ ment of scientists from various disciplines. The purpose of our Summer School was to bring a group of ex­ perts and participants together for the exchange of ideas and in­ formation in an informal setting and to promote interdisciplinary interactions. Out of many conceivable topics, we selected the following five as the main basis to broaden our knowledge and understanding I) Systematics 2) Structure 3) Electronic and Magnetic Proper­ ties 4) Spectroscopic Properties and 5) Lanthanide Geochemistry.