Celebrating 100 years of X-ray crystallography

A collection of articles contributed by speakers at the Bragg Centennial Symposium held in Adelaide on 6 December 2012 are introduced.

A tribute to W. L. Bragg by his younger daughter

A tribute to W. L. Bragg by his younger daughter is presented.

Sir Lawrence Bragg

An extract from the obituary for Sir Lawrence Bragg by M. F. Perutz [Nature (London), (1971), 233, 74–76] is given.

Background to the Nobel Prize to the Braggs

W. L. Bragg would have missed the Nobel Prize if his father had been awarded the prize together with von Laue in 1914. Fortunately, the Nobel Committee for Physics was aware of his contributions and decided to award the prize to W. H. Bragg together with his son in 1915, when they were both nominated.

Lawrence Bragg's interest in the deformation of metals and 1950–1953 in the Cavendish – a worm's-eye view

A research student's view of life in W. L. Bragg's Cavendish Laboratory from 1950–1953 is given. The use of the bubble raft in illustrating the properties of dislocations in crystals is described.

Lawrence Bragg, microdiffraction and X-ray lasers

The history of Bragg's law, life and work is reviewed with particular reference to the development of X-ray and electron microdiffraction. A summary of recent work applying the hard X-ray free-electron laser to problems in structural biology is given.

The Bragg legacy: early days in macromolecular crystallography

W. L. Bragg's critical role in encouraging, supporting and establishing the field of large-molecule crystallography is reviewed.

The early development of neutron diffraction: science in the wings of the Manhattan Project

Early neutron diffraction experiments performed in 1944 using the first nuclear reactors are described.

The significance of Bragg's law in electron diffraction and microscopy, and Bragg's second law

The significance of Bragg's law in electron diffraction is discussed, with particular emphasis on the differences between X-ray and electron diffraction. Recent developments in X-ray instrumentation in electron microscopy which enable single atoms to be imaged and identified using X-ray analysis within an electron microscope are described.

Evolution of diffraction methods for solving crystal structures

The practices for determining the atomic structures in crystals have changed greatly over the century since Lawrence Bragg introduced the trial-and-error method by which he solved structures for rocksalt, iron pyrite and other salts and minerals. Structure determinations for biological macromolecules first borrowed from the small-molecule tradition that evolved, notably adopting isomorphous replacement; subsequently, however, new approaches have grown to dominate, notably anomalous diffraction and molecular replacement.

Early days in drug discovery by crystallography – personal recollections

The neuraminidase inhibitors for treatment of influenza are an early example of drug discovery by crystallography.

An algorithm for the arithmetic classification of multilattices

A novel procedure for the characterization and the arithmetic classification of monoatomic multilattices in any dimension is proposed. The algorithm may be coded to provide an automatic classification procedure.

Equivalence of superspace groups

The standard settings of (3 + d)-dimensional superspace groups are determined for a series of modulated compounds, especially concentrating on d = 2 and 3. The coordinate transformation in superspace is discussed in view of its implications in physical space.

Bent perfect crystals as X-ray focusing polychromators in symmetric Laue geometry

The focusing properties of a bent Laue polychromator crystal are investigated by a semi-analytical approach based on the dynamical diffraction theory.

On the use of the C map in Patterson deconvolution procedures

The C map has been combined with implication transformation and vector-superposition techniques to improve the Patterson deconvolution method.

Continuous X-ray diffractive field in protein nanocrystallography

Structural imperfections play an important role in the formation of the diffraction patterns of membrane protein nanocrystals. Detailed analysis of the diffraction phenomenon shows that the scattering from such nanocrystals should be regarded in terms of a continuous diffractive field rather than a formulation based on discrete Bragg reflections.

Topological density of lattice nets

The multiplicity of the grid pattern formed by geodesic lines is included in the expression of the topological density of lattice nets.

Nominations for the Ewald Prize