May he rest in peace. He did a great job for all the crystallographers. Fabrizio Guzzetta Ph.D. student, Dept. Quimica Inorganica y Organica, UJI Castellon de la Plana Spain
2016-07-19 14:57 GMT+02:00 Alan Hewat <alan.he...@neutronoptics.com>: > *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. > 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 > ______________________________________________ > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Please do NOT attach files to the whole list <alan.he...@neutronoptics.com > > > Send commands to <lists...@ill.fr> eg: HELP as the subject with no body > text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > >
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