Neutron scattering

Thermal neutron scattering is a space-resolved spectroscopic technique which probes atomic motions at nanometric length scales and on time scales ranging from sub-picoseconds to about 10 nanoseconds. An important application is quasielastic neutron scattering (QENS) from proteins, which can be used to probe the internal stochastic motions in proteins. Since proteins contain a large amount of hydrogen atoms and incoherent scattering by the latter dominates by far all other contributions, QENS probes here essentially self-correlations in the dynamics of the hydrogen atoms. Each (hydrogen) atom in a protein participates in a variety of motions, ranging from fast local bond-vibrations to slow ``breathing motions’’ of the whole protein, which can be detected with flash photolysis and fluorescence techniques on time scales as long as seconds and even hours. As a result, the dynamics probed by QENS is characterized by power-law relaxation processes, leading to self-similarity in time, i.e. to an invariance under a change of the time scale.

Recent publications:

  • G. R. Kneller, Franck-Condon picture of incoherent neutron scattering PNAS USA, 30 August (online) 2018

  • G. R. Kneller, Asymptotic neutron scattering laws for anomalously diffusing quantum particles J. Chem. Phys. 145(4), 044103–7, 2016 (Editor’s choice 2016)