Incoherent neutron scattering studies of select inorganic systems

Thesis

Spectroscopic measurements are detailed within this thesis, utilising incoherent neutron scattering to examine the dynamics of various condensed-matter systems, from nanosecond to sub-femtosecond timescales. The body of this work is divided into two distinct areas of research.

I. Nuclear Momentum Measurements of Multiple Masses

Deep inelastic neutron scattering (DINS) is used to probe the nuclear momentum distributions and kinetic energies of individual atomic species in sodium hydride (both in bulk and as nanoparticulates within a silica matrix), enriched lithium-7 fluoride and lithium tetra-ammoniate. Extension of DINS to examine heavier (M>4amu) nuclei is detailed, accomplished by the application of a simple stoichiometric fixing technique within the standard DINS theory and analysis protocols. The validity and accuracy of such simultaneous measurements are discussed.

II. The Dynamics of Coordinated Ammonia in Zeolite A

Inelastic neutron scattering (INS) and quasielastic neutron scattering (QENS) are utilised in the examination of vibrational and stochastic dynamics of the ammonia molecule, as coordinated to the internal surface of a zeolite host. Both sodium and copper-exchanged forms of zeolite-A are studied, with proton-weighted, low energy phonon-modes and rotational processes being observed and assigned.

Authors: Seel, AG

• Alternative title: I. Nuclear momentum measurements of multiple masses, II. The dynamics of coordinated ammonia in zeolite A
• Publication date: 2012
• DOI: 10.5287/ora-6rdzbmmv9
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: dynamics; neutron compton scattering; inelastic neutron scattering
• Subjects: Chemistry & allied sciences; Inorganic chemistry; Spectroscopy and molecular structure; Condensed Matter Physics; Solid state chemistry; Physical & theoretical chemistry