Commission on Electron Crystallography


Triennial Report 1996-1999

 The Commission has been involved in a number of Schools on Electron Crystallography. One of these was held in Erice, Italy, in 1997 and directed by D. L. Dorset (Secretary of the Commission). There were 20 lecturers from 10 countries and 228 students from 24 countries. Joint sessions were held concurrently with the NATO Advanced Study Institutes on Direct Methods of Solving Macromolecular Structure. This school was supported by the IUCr as was a School on Electron Crystallography held in Stockholm, Sweden, in 1998. This school, organised by S. Hovmõller and X.-D. Zou, was also well attended and stimulating with a wide range of international participants and lecturers (one being J.W. Steeds, Chair of the Commission). Another similar school is being organised by S. Hovmõller and X.-D. Zou in Nantes, France, in 1999.

Members of the Commission have been influential in organising and contributing to a large number of conference sessions related to electron diffraction. The list is too long to give in detail but includes two sessions of the 14th International Congress of Electron Microscopy in Cancun, Mexico, one on Electron Crystallography (S. Hovmõller) and another on Convergent-Beam Electron Diffraction (J.W. Steeds). Also worthy of report is the election of D.L. Dorset as a member of the US National Committee for Crystallography (1996-1998).

D. L. Dorset contributed a paper to a special issue of Acta Crystallographica, entitled 'Electron Crystallography - Accomplishments and Challenges' [Acta Cryst. (1998). A54, 750-757].

D. L. Dorset is a member of the Programme Committee for the Glasgow Congress. The Commission is organising three microsymposia on Quantitative Electron Diffraction and Microscopy (Chairs D. van Dyck and J.K. Gjonnes), The Phase problem in Electron Crystallography (D.L. Dorset and R. Vincent) and Structure Solutions from Powders using Electron and Powder Diffraction Techniques (S. Hovmõller with R.J. Cernik of the Commission on Powder Diffraction).

The decision for gas electron diffraction to be moved to the Commission on Structural Chemistry is regarded as a sensible rationalisation. The Commission effectively covers three communities at present. First there is the dynamical diffraction community for high-energy electrons using convergent-beam techniques. Second, there are the former X-ray crystallographers who are transferring well developed techniques from that field to electron crystallography. Third, there is the surface electron diffraction community. The one important community not represented at present is biochemical electron microscopists largely in the field of membrane proteins who rely on Fourier transformation of averaged image intensities to solve crystallographic problems. It would be an interesting challenge to try to extend our dialogue to this community in the next few years.

J.W. Steeds, Chair