John White was distinguished for his application of neutron scattering methods in physical chemistry - using contrast from the dynamics, isotopic replacement and spin to selectively simplify the scattering patterns of molecular crystals, molecular liquids, polymers, adsorbed molecules and biological systems. He obtained a quantitative understanding using theoretical calculations and molecular dynamics simulations.
John was among the first to assign densities of phonon states and to record the phonon dispersion from single molecular crystals, as well as exploring the sensitivity of molecular rotational tunnelling as a ‘local’ probe of crystal and surface adsorption potentials. His scattering studies of methane and of isoelectric ammonia on graphite were among the first to examine the structure and dynamics of adsorbed monolayers with neutrons.
The same contrast methods show the mechanisms by which molecular ‘templates’ direct gel structure into zeolitic and inorganic biological forms and can be used in designing the rheology of industrial emulsions. John was the first British Director of the Institut Laue–Langevin, Grenoble and the 2015 winner of the Asia-Oceania Neutron Scattering Association Prize.
Professor John White CMG FRS died on 17 August 2023.
Interest and expertise
Protein aggregation, Emulsions, Chemical hydrogen storage, Neutron scattering, X-ray diffraction, Denaturation