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IUCr 1993 Triennial Report - International Centre for Diffraction Data (ICDD)

The ICDD is the new name for what used to be known as the JCPDS. In my capacity as IUCr Representative to the ICDD, during the triennium I attended several of their semi-annual meetings and two special meetings of ICDD with IUCr representatives.

The ICDD is chartered as a not-for-profit organization. Its purpose can be described as to gather, cull, edit, and disseminate useful diffraction data, mostly powder data useful for crystalline phase identification, in the international arena. It is a substantial organization with a paid staff of more than 25 persons under the direction of General Manager J. Messick, its own building in Swarthmore (now Newton Square) in Pennsylvania, and 124 volunteer members in more than 10 countries. It is governed by a non-staff Board of Directors chaired, during this triennium, by D. Smith followed by L. Frevel and now by G. G. Johnson. A great amount of the work of acquiring new or improved powder diffraction patterns, of setting policy and new directions, of generating new ideas for services, and of testing out new products and ideas is carried out by volunteers organized into Committees, Sub-committees and Task Groups.

The international aspect of the ICDD character continues to grow. Currently, about 60% of the ICDD's income is from overseas sources and 63% of the Grant-in-Aid recipients are outside the USA. Two of the full members of the Board of Directors and several consultants are European. Many of the ordinary members are Asian, Australian or other non-US persons. ICDD operates a very substantial Grants-in-Aid programme which directly generates powder diffraction patterns deemed wanted but which are not otherwise available. The annual funding for the programme is in excess of US$300000.

The ICDD also gives grants in support of selected meetings and Workshops. It gave some financial support and ran a Workshop at the 1990 Satellite Meeting on Powder Diffraction in Toulouse, contributed US$15000 to the CPD-organized meeting Accuracy in Powder Diffraction II at NIST in May 1992 (which was used to pay travel for invited lecturers, who would provide sound and timely manuscripts for the Proceedings, which were actually issued about six months after the meeting), paid the travel of one invited teacher/lecturer at the International School of Crystallography: Computational Methods in X-ray Powder Diffraction Methods in Aswan, Egypt, 16-26 January 1993 (co-organized by the CPD), and will contribute US$5000 to the 1993 Satellite Meeting on Powder Diffraction. The ICDD also makes cash contributions to and runs Workshops at various other meetings and Schools all over the world.

The ICDD operates a Crystallography Scholarship Awards programme, which provides two awards per year. The two awards in 1992 went to graduate students in the UK.

The ICDD has now adopted the CIF/STAR format as standard for the archiving and interchanging of PDF-3 (consisting of digitized whole patterns) data and future databases. PDF-3 is to be based on fully digitized patterns. A few hundred are now on hand and they are coming in at a rate of about 500-600 per year. There is a growing and spreading recognition that a great many analyses formerly undertaken with the `d & I' type of database can be performed much better with digitized full patterns. Included are quantitative phase analysis, phase identification in complex mixtures and extracting useful information from the `pathologies' of the patterns, such as various effects characteristic of different clays. Such patterns might also be used for ab initio structure determinations.

The ICDD has dozens of projects in progress simultaneously, including several round robins:

(i) Instrument parameters (Jenkins, ICDD);

(ii) Automated peak finding (Ryba, Penn State University);

(iii) Statistical process control (Blanton, Eastman Kodak);

(iv) Profile fitting (Cline, NIST);

(v) Preferred orientation (Diffraction Problems Subcommittee).

An ICDD Task Group was set up, with R. Snyder as Chair, to conduct a project jointly with the CPD on Crystallite Size and Microstrain. One aspect of the work is expected to be a Round Robin on Crystallite Size and Microstrain. (Dr Fiala chairs the CPD's Task Group on this.)

In accord with the adage that in science and technology nothing stands still, the process of phase identification by `search-match' is also becoming more sophisticated, powerful and broadly applicable. Now, it is being shown that even electron powder diffraction data without recorded intensities can be used very successfully. (In fact, the new electron diffraction database is a current best seller among the ICDD offerings.) A large part of the key to this new success is a search method that simultaneously uses the electron powder diffraction database, the database formed from the 150 000 cell constants recorded in Crystal Data (the NIST publication assisted by the ICDD) and the X-ray powder diffraction database (PDF). The electron diffraction database may be used to develop several guesses about what the material might be and the other databases then are used in consistency tests to narrow down the range of possible candidates. Remarkable success rates were reported by the speakers and by two or three members of the audience at the October 1991 ICDD technical meeting.

In 1991 and 1992, the ICDD operated the `clinics' on X-ray fluorescence and X-ray diffraction in 1992 at Swarthmore College. These are the `clinics' that were established and operated by Henry Chessin at SUNY, Albany for more than 20 years.

The ICDD publishes the journal Powder Diffraction. The Editors of this and the Editors of the Journal of Applied Crystallography attempt to exchange or transfer manuscripts submitted to one journal which might better belong in the other. In so far as this Representative has determined, this cooperation is working well.

In early 1993, the ICDD moved from their Swarthmore address into their new 25000 square foot building located at the Newton Square Corporate Campus, 12 Campus Blvd, Newton Square, PA 19073-3273, USA. They can now carry out all of their operations at a single location, which had not been possible for years in the Swarthmore building.

23 April 1993                             R. A. YOUNG, Representative

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