Materials are
essential to our
technological society: semiconductors in the electronic industry,
zeolites as catalysts in the petrochemical industry, ceramics in
medicine and
engineering, and, possibly in the future, high-temperature
superconductors in electrical engineering.....
In order to understand the properties of these materials and
to
improve them, the atomic structure has to be
known. An effective way to do this is by means of diffraction
techniques using neutrons from nuclear reactors and particle
accelerators or X-rays from X-ray tubes and synchrotrons. The
single crystal diffraction technique, using relatively large
crystals of the material, gives a set of separate data from
which the structure can be obtained.
However, most materials of technical interest cannot grow large
crystals, so one has to resort to the powder diffraction
technique using
material in the form of very small crystallites. The drawback
of this conventional powder method is that the data
grossly overlap, thereby preventing proper determination of the
structure. The "Rietveld Method" creates an
effective separation of these overlapping data, thereby
allowing an
accurate determination of the structure.
The method has been so successful that nowadays the structure
of materials, in the form of powders, is routinely being
determined, nearly as accurately as the results obtained by single
crystal
diffraction techniques. An even more widely used application of the
method is in determining the components of chemical mixtures. This
phase analysis is now
routinely used in industries ranging from cement
factories to the oil industry.
The success of the method can be gauged by the publication of more than
a thousand scientific papers yearly using it.
___________________________________________________________________________________________________________
Hugo Rietveld was
born
in The Hague, The Netherlands, on 7
March 1932. After completing Grammar School he went to Australia and
studied physics at the University of Western
Australia in
Perth.
In 1964 he obtained his Ph.D. degree with a thesis entitled
"The
Structure of p-Diphenylbenzene and Other Compounds", a single
crystal neutron and X-ray diffraction study. This investigation was the
first single crystal neutron diffraction study in Australia
and was
conducted at the nuclear reactor, HIFAR, in Sydney.
In 1964 he became a research officer at the Netherlands
Energy Research Foundation ECN at Petten, The Netherlands,
and was mainly involved in neutron powder diffraction studies of
uranates and other
ceramic compounds.
After a scientific and managerial career with ECN he retired
in 1992.
