History

Crystallography at Lausanne,

Up to the early seventies, no French speaking university in Switzerland had a chair in crystallography. In Lausanne, various attempts during the sixties to create such a chair were unsuccessful. It seems that these efforts were lead by the physicists, whereas the chemists appeared to be hardly interested. The mineralogists were reserved since they already operated diffraction equipment and wished to develop their own X-ray laboratory for mineral analysis and identification. For two years, in the academic years starting in 1968 and 1969, a course in crystallography for the second-year physics students of both the University of Lausanne (UNIL) and the newly created Ecole Polytechnique Fédérale (EPFL) was given by Samuel Steinemann, a professor of solid-state physics at the University. When he wished to relinquish this charge, the University decided to hire a travelling lecturer (chargé de cours). I was at that time a member (Oberassistent) of the Institute of Crystallography at ETH-Zürich headed by professor Fritz Laves, and on his recommendation I gave the course from 1970 to 1972 on Saturday mornings, travelling back and forth between Zürich and Lausanne. At that time, I did not have any equipment in Lausanne and no relations with University personnel, except with professor Steinemann and his teaching assistant. When in the spring of 1973 I decided to abandon this charge, I was offered a chair in crystallography and the creation of an Institute of Crystallography attached to the Physics Department (Section de physique) of the University, starting with the winter term of 1973. At the same time, EPFL agreed not to create its own crystallography and to borrow from UNIL any crystallographic teaching and services it might require.

The fledgling institute started with a lonely professor, Fr. 500'000.- to buy equipment, some empty rooms in the brand-new Bâtiment des sciences physiques, and a polite interest of the Physics Department. I also was promised a relatively high-level collaborator, a maître assistant. The first scientific contact, when the rooms were still empty, was established by a post-doctoral fellow from the Chemistry Department, Alan Pinkerton (now professor at the University of Toledo, Ohio). This contact developed in a long scientific collaboration and a lasting friendship. Alan transformed himself into a capable chemical crystallographer, despite of his initial wishes, and was our antenna and contact with Chemistry for many years. In the spring of 1974, a Syntex P21 4-circle diffractometer was installed (it still functions today), and also a Guinier powder system, 2 precession cameras and a Weissenberg camera. Walter Petter from ETH-Zürich helped to install the laboratory in the summer of 1974. In the fall of 1974, Gervais Chapuis was appointed maître assistant; he has since moved up through the levels of assistant professor (1979) and associate professor (1981) to ordinary professor (1991). Subsequently, we also obtained the positions of two teaching-assistants (assistants diplomés). The first graduate student started in the spring of 1976. In 1982, we were allotted a half-time secretary, and in 1988 the position of a service crystallographer (chef de projet) was created and occupied by Kurt Schenk. Since 1990, we have initiated and lead a project for the construction of a beamline at the European Synchrotron Radiation Facility (ESRF) in Grenoble. This effort has developed into the Swiss-Norwegian Beamline (SNBL) funded by the Swiss and Norwegian National Science Foundations, Swiss and Norwegian Universities and Institutes of Technology and the Basel chemical industries.

Today, the Institute of Crystallography has 12 collaborators: the four persons named above occupying 3.5 stable staff positions, three graduate students, three post-doctoral fellows and two scientists responsible for the SNBL. Three of the temporary positions are paid by the University (2 assistants diplomés, 1 premier assistant). A half-time position of professor, occupied by Jean-Pierre Weber, the head of the SNBL project, is a compensation of the time Gervais Chapuis spends as advisor to the Rectorat of the University on informatics. The other positions are paid by grants of the Swiss National Science Foundation.

The Institute possesses three 4-circle diffractometers, the Syntex P21 mentioned above, an Enraf-Nonius CAD-4 acquired in 1981, and a KUMA installed in the spring of 1995. This last instrument is used for the construction of a high-resolution two-dimensional detector in collaboration with the Polish firm KUMA. We also operate a Philips powder and texture diffractometer. A Silicon Graphics Indigo 2 workstation serves to model phase transitions and aperiodic crystal structures. Differential thermal analysis is used to detect phase transitions. The main subjects of research are:

Modelling and refinement of crystal structures:
orientational disorder in fullerene structures C60 and C70, anharmonic motion and bonding electron densities in simple inorganic compounds, novel refinement methods with respect to raw observations and estimation of the uncertainty of the results.

Aperiodic structures:
determination of modulated crystal structures, development of mathematical tools for the refinement of such structures, twinned modulated structures, application of the methods of molecular dynamics to the analysis of the mechanisms of phase transitions.

Development of a novel two-dimensional detector for accurate intensity measurement and efficient recording of two-dimensional w-q intensity profiles of individual reflections.

The Institute leads a consortium of Swiss and Norwegian Universities for the construction of the SNBL mentioned above. Synchrotron radiation will be an increasingly important tool for our research projects.

Initially and for many years, the Institute offered its scientific equipment and help freely to anybody who was interested in determining crystal structures, identifying materials or aligning crystals. Interested scientists were only required to have successfully attended a two-week course in X-ray crystallography. This induced many diploma and doctoral students from chemistry to spend some time with us. Since 1988, service crystallography is taken care of by Kurt Schenk. He determines today some 20 to 30 structures a year, identifies substances with powder methods and prepares pole figure diagrams with the texture goniometer for chemists, physicists, materials scientists and various commercial firms. He also is at the service of everybody wishing to use our equipment. However, the demand for crystal structure determinations for chemical analysis of professor Carlo Floriani's research group (Chemistry Department UNIL) by far exceeds the capacity of our institute. Prof. Floriani has therefore acquired two 4-circle diffractometers (MSC-Rigaku) which he operates with a post-doctoral fellow and the collaboration of Kurt Schenk. About 100 structures per year are determined from data measured with these instruments, either in Lausanne or in Italy. Non-standard problems tend to be referred to Kurt Schenk. The Earth Science Department UNIL maintains an independent X-ray laboratory dedicated essentially to the identification of powder samples.

Courses in crystallography are compulsory for second year physics and materials science students, and for fourth year chemistry students (UNIL and EPFL). A two-week course on diffraction techniques and structural data bases is offered to all interested undergraduate and graduate students. Optional courses on structure determination and general diffraction theory are offered to advanced students. Graduate students in crystallography have degrees in physics or in chemistry. They work on diverse fundamental aspects of crystallography and become also familiar with the techniques of crystal structure determination. However, they face the job market as physicists or as chemists.

Article paru dans 24 Heures le 19 décembre 1983 pour les 10 ans de l'Institut de cristallographie.

L'Institut de cristallographie, article paru dans l'agefi 15 août 2002 dans le cadre du congrès mondial de l'Union Internationale de cristallographie à Genève.