A sad day indeed for powder diffraction. The impact of Hugo Rietveld's work can
never be overestimated. Developing and applying the Rietveld method has been
central to my work for >30 years.
Cheers
o----------------------------oo0oo----------------------------o
Ian Madsen
Honorary Fellow
CSIRO Mineral Resources Flagship
Private Bag 10, Clayton South 3169
Victoria, AUSTRALIA
Phone +61 3 9545 8785 direct
+61 3 9545 8500 switch
+61 (0) 417 554 935 mobile
FAX +61 3 9562 8919
Email ian.mad...@csiro.au
o----------------------------oo0oo----------------------------o
________________________________
From: rietveld_l-requ...@ill.fr <rietveld_l-requ...@ill.fr> on behalf of Alan
Hewat <alan.he...@neutronoptics.com>
Sent: Tuesday, July 19, 2016 10:57:44 PM
To: rietveld_l@ill.fr
Subject: The passing of Hugo Rietveld
The passing of Hugo Rietveld, on the 50th anniversary of Rietveld Refinement
and the 100th anniversary of Powder Diffraction
It is our sad duty to report the death of Hugo Rietveld at the age of 84 after
a short illness. He leaves behind his wife, a son and two daughters to whom we
extend our heartfelt sympathy on behalf of the more than one thousand members
of the Rietveld Mailing List.
Hugo was born on the 7 March 1932 in The Hague and migrated to Western
Australia with his family, where in 1957 he enrolled at the University of WA at
the same time as Brian O’Connor and Syd Hall. He obtained his Ph.D. under the
supervision of Ted Maslen who had studied under Dorothy Hodgkin at Oxford. Hugo
pioneered single crystal neutron diffraction at Lucas Heights Sydney with Terry
Sabine, and their first paper was published in Nature in 1961.
Clews C J B, Maslen E N, Rietveld H M and Sabine T M (1961) Nature 192
154<http://www.nature.com/nature/journal/v192/n4798/abs/192154a0.html>
“X-Ray and Neutron Diffraction Examination of p-Diphenylbenzene"
Hugo's experience with manual data collection and refinement convinced him of
the need to computerise such tasks, and at Lucas Heights and the UWA he
programmed two of the first IBM-1620
mainframes<http://www-03.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP1620.html>
in Fortran-II. After obtaining his Ph.D. in 1964 with Dorothy Hodgkin as
external examiner, (she had received the Nobel Prize for her work on penicillin
and vitamin B12), he joined the neutron diffraction group of the Reactor
Centrum Nederland in Petten and his interest turned to powder diffraction
because large single crystals were not available for the inorganic materials of
interest.
The young group at Petten including Bert Loopstra, Bob van Laar and Hugo
Rietveld first addressed the problem of overlapping powder reflections by using
a relatively long neutron wavelength (2.6 Å) with a pyrolytic graphite filter.
This spread out the long d-spacing peaks, allowing more of them to be resolved,
and is still a good solution for the magnetic structures in which they were
interested. However, for structure refinement many peaks were still unresolved,
and the shorter d-spacings needed for high atomic resolution could not even be
seen.
In a 1966 paper, Hugo already used intensities from overlapping Bragg peaks.
Along with others with the same problem, he then tried to fit multiple peaks to
overlapping regions, but with limited success. As well, a neutron powder
pattern took a whole week to collect, and the local Electrologica-X1
computer<https://ub.fnwi.uva.nl/computermuseum//X1.php> was less powerful than
the IBM-1620 - and programmed in Algol. It was there and then that the
brilliantly simple but profound idea arose of refining the crystal structure
together with the parameters describing the peak positions and profiles all
together, as published in the famous 1969 paper.
Rietveld H M (1969) Journal of Applied Crystallography 22
65-71<http://scripts.iucr.org/cgi-bin/paper?a07067>
“A profile refinement method for nuclear and magnetic structures”
Hugo distributed his Algol refinement
program<http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/46/087/46087996.pdf>
widely, but very few papers were initially published using the method.
Discouraged by the limited funding available for neutron diffraction, he
successfully applied to become head of the library department at Petten.
One of us (AH), who had also completed his Ph.D. at Lucas Heights in 1970 and
who had moved to Harwell, encountered the same problems with neutron
diffraction for structural transitions. On the advice of George Bacon, AH
visited Hugo in 1971 and brought back Hugo's new Fortran-II version of the
profile refinement program. A Harwell
version<http://hewat.net/science/papers/1973_The_Rietveld_Program_for_the_Profile_Refinement_of_%20Neutron_Diffraction_Powder_Patterns_AERE_R7350-von_Dreele_annotations.pdf>,
modified to model the anisotropic vibrations preceding structural transitions,
was very successful, both at Harwell and with Brian Fender's students at
Oxford, in particular Tony Cheetham and Bob von Dreele.
In 1973, when the UK joined the EEC and AH moved to ILL in Grenoble, another
Oxford student (WIFD) performed his first neutron powder experiments on AH's
new D1A high resolution diffractometer, where a powder pattern took only one
day to collect, and later only one hour. Again this work was very successful,
and the number of papers using what Terry Sabine, in 1978, christened the
"Rietveld Method" exploded, supported by new computer programs including those
of the early Oxford-Grenoble champions Bob von Dreele and Juan
Rodriguez-Carvajal. Yet it was not until 1977 that R.A. Young and colleagues
applied the method to X-ray powder diffraction, leading to further rapid growth
in the number of publications. Thousands of X-ray publications using Rietveld
Refinement are now published every year.
Perhaps the greatest acknowledgement of Hugo’s work was his receipt of the 1995
Aminoff Prize, awarded by the Royal Swedish Academy of Sciences, Two of us (AH
and WIFD), along with Juan Rodriguez-Carvajal and Ivar Olovsson, were there to
witness Hugo, accompanied by his wife and children, receive his accolade from
the King of Sweden with typical modesty, delight and genuine astonishment at
the pervasive influence of his Method across the sciences around the world. And
beyond the world - in December 2012 he was thrilled to receive an e-mail from
David Blake of the CheMin team of the Mars Science Laboratory rover, Curiosity,
who wrote saying that he did not think they could have convinced NASA to send
an X-ray powder diffractometer to Mars without the Rietveld Method.
After almost 50 years, the Rietveld Method has returned to its origins in the
Netherlands, with the third of us (LvE) completing a fast new high resolution
neutron powder diffractometer (PEARL) on the Delft reactor. Hugo Rietveld lived
to see that, and last year was the guest of honour at the opening of this new
diffractometer. He, who had been honoured throughout the world for his
achievement, was honoured in his own country by a new generation working with
neutron powder diffraction and Rietveld Refinement.
Having achieved all of that, and with a loving family and friends, he will
surely rest in peace.
[https://ssl.gstatic.com/ui/v1/icons/mail/images/cleardot.gif]
Alan Hewat (AH), Bill David (WIFD) and Lambert van Eijck (LvE) July 2017
______________________________________________
Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE
<alan.he...@neutronoptics.com> +33.476.98.41.68
http://www.NeutronOptics.com/hewat
______________________________________________
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