An obituary of Niels Hansen by Claude Lecomte
Professor at the Faculty of Sciences in Nancy (France), Niels Hansen
passed away at the age of fifty-seven following a long period of illness.
After brilliant studies at the University of Aarhus, in Denmark, he prepared his doctorate
in physical sciences at the University of New York in Buffalo under the supervision of
Professor P. Coppens, a world-reputed crystallographer. In his thesis, he put forward a
model to describe the electron density in solids, the importance of which is such that his
name is now associated with it. Thirty years later, the Hansen-Coppens model is still the
model most used by researchers in crystallography to describe the chemical bonding and the
physical properties of materials related to the electron density. Understanding the behaviour
of electrons in solids continued to be his main theme of research in the Hans Meitner
Institute in Berlin, then in Nancy where he became Professor in 1983, in the Laboratory
of Crystallography and Modelling of Mineral and Biological Materials.
His recent works, subsidised by the French National Research Agency, concern the comprehension
of the piezoelectric effect which involves generating an electric field in a material such
as quartz when submitted to pressure. This effect has a large number of applications in
everyday life, from gas igniters to cell phones sensors and injectors. Understanding this
phenomenon at the atomic level is a very important for the conception of higher performance
A brilliant researcher of international status, while at the same time extremely discrete and
kind, Professor Hansen was always at the disposition of PhD students and other researchers
within the laboratory. He remained courageous throughout his illness, was a great contributor
to the development of our laboratory and his absence will be greatly felt.
20th Dec. 2007 - Crystallographers Online - Copyright © International Union of Crystallography