Seminar: Mass-resolved neutron spectroscopy

 Dr. Matthew Krzystyniak; ISIS Science & Technology Facilities Council, UK

Date: Tuesday, 25th April, 2017, from 10:00 to 11:00 at KFKI Campus, Bldg. No. 1, Conference room

Abstract:  Neutron Compton scattering is a unique experimental technique made possible by the development of epithermal neutron sources, such as the ISIS source of the Rutherford Appleton Laboratory in the UK. The measurement of nuclear momenta by high-energy neutron Compton scattering relies on the fact that the energy and momentum transferred in the scattering process are sufficiently large, such that the so-called impulse approximation is an accurate starting point. In this limit, the dynamic structure factor measured in neutron Compton scattering for a given nucleus covers the whole energy range of its motional modes. This includes translational and rotational modes, followed by lattice and internal molecular vibrations.

Since its birth, the neutron Compton scattering technique has been employed to study proton momentum distributions in quantum fluids and solids, metal hydrides, gas and charge-storage media, etc. Beyond the proton,  recent instrument developments towards mass-resolved neutron spectroscopy offer the prospects of access to the nuclear momentum distributions of heavier nuclides including deuterium, helium, lithium, carbon, oxygen, and fluorine.

I will present some examples of recent mass-resolved neutron spectroscopy work advocating an unprecedented combination of ab initio tools and neutron scattering techniques employed for the first time in the context of the characterisation of nuclear quantum chemical dynamics in the solid state with special emphasis on hydrogen bonded molecular crystals.

Organised by Margit Fabian