cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1710096
title: Structure and Reaction Kinetics of Phenylacetylene Hydrogenation in a Porous Titania Catalyst

description: This project aims to study the confinement of phenyl acetylene in the pores of mesoporous titania catalysts for the conversion into styrene.  Specifically, neutron scattering will be used to monitor the structural changes during the reaction and thus elucidate both the kinetics of the process as well as the distribution of the liquid within the pore.  This will be coupled with in-situ measurements using NMR spectroscopy to continuously monitor independently the reaction.
DOI: 10.5286/isis.e.rb1720335
title: Understanding nanoscale inhomogeneities in industrial films

description: The world wide trade in chemicals is shipped via large tankers. These tankers have their holds coated in epoxy resin based systems. The major issue in their use is the waste and environmental damage produced when the tanks are washed and refilled with a different system, for example changing from methanol to acetone. The coatings are known to absorb the small molecules and this leads to stress and ultimately degradation of the films, in addition to cross contamination. The process of making the coatings is far from ideal and results in a range of inhomogeneities on the nanoscale.  We propose to study films of these coatings prepared under a range of conditions, (primarily changing the curing environment) before, during and after exposure to a range of deuterated solvents, in the hydrogenous matrix.
DOI: 10.5286/isis.e.rb1720389
title: Motional Dynamics of Positively Charged Muonium in Anatase, Brookite and Rutile Titanium Dioxide

description: We propose a series of measurements on anatase and brookite Titanium Dioxide (TiO2) to investigate the motional dynamics of positively charged Mu centres and their transition out of the paramagnetic state. These measurements utilize the implanted muons as an experimentally accessible analog to Hydrogen. Hydrogen impurities in TiO2, intentional or unintentional, have been shown to greatly modify the electrical properties of the bulk materials. By implanting muons in these bulk materials under zero applied field conditions, we can directly observe how Hydrogen is likely to behave and with this greater understanding lay the groundwork for potential technological applications that will rely on understanding the fundamental behavior for the hydrogen impurities in these (stable) phases of TiO2. Proposed work is a key part of Mr. J.A. Horn (McNair Fellow at Northern Michigan) research project.
DOI: 10.5286/isis.e.rb1720442
title: An Investigation on the claim of Universal Dynamic Magnetism of Ytterbium Pyrochlores with the B-site disordered Yb2GaSbO7

description: Ytterbium pyrochlores (Yb2B2O7) have garnered a significant amount of interest due to the claim of the realisation of the quantum spin ice state in Yb2Ti2O7 (Ross et al., Phys. Rev. X, 1.2 (2011): 021002). In a recent study, Hallas et al. (Hallas et al., Phys. Rev. B. 93.10 (2016): 100403) have claimed that all Yb2B2O7 exhibit universal dynamic magnetism associated with the broad heat capacity feature, suggesting a hidden order parameter. Recent physical property measurements, polarised neutron scattering and muSR studies on Yb2GaSbO7 (YGSO) (Hodges et al., Journ. of Phys.: Condens. Matt. 23.16 (2011): 164217) suggest that it exhibits different behaviour compared to those studied by Hallas et al. We propose to measure the inelastic scattering spectra for 6 days on LET of YGSO with a dilution fridge with the objective of testing the claim of universal dynamic magnetism among Yb2B2O7.
DOI: 10.5286/isis.e.rb1810173
title: Intrinsic defect structures in zinc oxide

description: Zinc oxide is an important semiconductor, but its use in a wide range of applications is limited by the difficulty in doping p-type. This is believed to be related to the nature of the intrinsic defects, which cause a self-compensation of free carriers. We plan to determine the defect structures in nominally stoichiometric zinc oxide using single-crystal diffuse neutron scattering. Our previous measurements indicate that various defects contribute to the diffuse scattering along with the thermal diffuse scattering. We aim to separate the various contributions via their different temperature dependencies. Hence we propose to study single-crystal zinc oxide mounted in a furnace as a function of temperature using neutron Laue diffraction on SXD.
DOI: 10.5286/isis.e.rb1810461
title: Understand the role of dimensionality on heavy fermion physics and quantum criticality in CeCo2Ga8: Inelastic neutron scattering study

description: Dimensionality plays an important role in determining the anomalous non-Fermi liquid properties in heavy fermion systems. So far most heavy fermion compounds are quasi-two-dimensional or three-dimensional. CeCo2Ga8 shows a non-Fermi liquid behaviour in the resistivity and heat capacity at low temperature. Magnetization result suggests the typical behavior for a one-dimensional spin chain from 300 K down to 20 K, and first-principles calculations predict flat Fermi surfaces for the itinerant f-electron bands. These suggest that CeCo2Ga8 is a rare example of the quasi-one-dimensional Kondo lattice. We propose to carry out low temperature inelastic neutron scattering measurements down to 100 mK to study a across over from the non-Fermi liquid to Fermi liquid behaviour in E/T scaling observed at a local quantum critical point on OSIRIS spectrometer.
DOI: 10.5286/isis.e.rb1810561
title: High energy dependence of countable spin excitations in CaFe2O4 using backscattering on OSIRIS:

description: Recent high resolution spectroscopy has found countable and discrete excitations in the two dimensional magnet CaFe2O4.  This work aims to track these excitations to higher energies using neutron backscattering.  Through a measurement of energy positions and line widths we hope to observe where these excitations cross over to conventional and classical spin-waves where every wavelength corresponds to a single energy.  Based on this, we aim to discover how magnetic excitations can be trapped or localized in real space to create materials with similar properties to that of photonic band gap materials applied to optics.
DOI: 10.5286/isis.e.rb1810675
title: Low energy magnetic excitations in Sm based pyrochlores

description: Few studies of Sm pyrochlores are reported in literature. It is believed that these coumpounds remain in a disordered state down to the lowest temperatures, mainly due to the very weak antiferromagnetic exchange interaction and the small magnetic moment of the Sm ions. Our results at low temperatures indicate that the compounds proposed to be studied here undergo a phase transition below 500 mK, and its ground state may present similar surprising results as other pyrochlore systems.
DOI: 10.5286/isis.e.rb1810806
title: Temperature dependence of the diffuse magnetic scattering in CsNiCl3: SXD data for modelling: Continuation Rb1720516.

description: The compound CsNiCl3 crystallises in a hexagonal structure and is comprised of chains of NiCl6 octahedra along the c-axis and Cs in-between acting as a spacer to separate the NiCl6 chains. In this proposal, we would like to complete a previous experiment in particular to capture an intermediate magnetic phase and propose to collect additional data sets at 4 K and 4.35 K, i.e. just below in within this phase. At 10K we will observe the diffuse magnetic signal in the paramagnetic phase. For this we ask for 4 days on SXD equipped with an orange cryostat.
DOI: 10.5286/isis.e.rb1720097
title: Evolution of magnetic ordering in three oxide arsenides containing CrO2 layers: Ba2Cr2MnAs2O2, Sr2CrMn2As2O2 and Sr2Cr2MnAs2O2

description: This experiment will probe the evolution of magnetic ordering in compounds with square planar Cr2+ ions in CrO2 oxide layers, and the interaction of these moments with Mn2+ and Cr2+ moments in the intervening (Cr0.5Mn0.5)As or MnAs arsenide layers. The compounds will be compared with the isostructural Ba2Cr3As2O2 and Sr2Cr3As2O2 which have spin reorientation transitions at ~ 300 K due to interplay of the two Cr2+ sublattices. Preliminary single-temperature measurements have been used to examine the obvious question of Cr/Mn order vs disorder showing that Cr2+ is the sole occupant of the oxide layer in all three cases. These measurements furthermore show that all three compounds show magnetic long range order, and the ordered models are different. Thus a full variable temperature probing of magnetic long range order is required.
DOI: 10.5286/isis.e.rb1720359
title: Determination of the Spinon Confining Potential in a 1D, Spin-1/2 XXZ Antiferromagnet

description: SrCo2V2O8 is a quasi-1D, S-1/2 antiferromagnet with XXZ anisotropy. Weak interchains coupling result in long-range magnetic order at a finite temperature TN. A spinon continuum is observed above TN while below TN a series of resolution-limited sharp modes occur. The modes are due to spinons bound into pairs by the interchain coupling which acts as a confining potential. A new theory describes the bound modes except for a small but significant shift in the mode energies and intensities due to the interchain coupling. To understand the confining potential better and to achieve more accurate agreement between theory and experiment, the full Hamiltonian of SrCo2V2O8 including the details of the complex interchain coupling is needed. The goal is to measure the interchain dispersions in order to extract the Hamiltonian that will be included in the the theory as a random phase approximation.
DOI: 10.5286/isis.e.rb1810013
title: Oxide ion defects distribution and conduction pathways in apatite-type silicates

description: Apatites are  functional materials with important potential applications as solid electrolytes, and also as  biomaterials, ceramics for nuclear waste immobilisation, and catalysts. In apatite-type solid electrolytes, the conductivity depends on the number and the location of oxide ion interstitials, as well as energetically favourable carrier migration pathways within the structure. The location of interstitial oxygen atoms in apatite silicates has been controversial, with different pieces of work, based on powder diffraction data, reporting excess oxygen atoms at different sites. The proposed experiments will be carried out on high-quality single crystals and will provide an accurate structural characterisation of these materials ad a better understanding of the structure-property relationships.
DOI: 10.5286/isis.e.rb1810081
title: The Effect of Sorbate-Framework Interactions on Controlled Drug Release by Zeolites

description: To understand the controlled release of drug molecules from zeolite hosts, we propose to study using INS the interactions of beta-blocker atenolol with the Brønsted acid sites in potential zeolite candidates for its controlled release, H-FAU (Si/Al=5), H-FAU(Si/Al=80) and zeolite beta. The H-FAU (5) sample releases the drug over a 24 hour period, whereas the H-FAU (80) sample releases over 10 days. This is counterintuitive as the much larger number of Brønsted acid sites in H-FAU (5) should slow the molecular mobility through interactions with the sorbate. QENS experiments (RB1710135) suggest that the fundamental freedom of mobility is indeed higher in the H-FAU (5) sample, and diffraction data suggests more lattice distortion upon drug adsorption in the slower releasing H-FAU (80) sample. We aim to rationalise these observations through probing sorbate-Brønsted site interactions.
DOI: 10.5286/isis.e.rb1810096
title: The dynamical transition in dry proteins?

description: Water plays a critical role in determining the structure and function of biological system. A hydration level, h~0.2 g water/g protein, is often found to be the minimum requirement for the dynamical transition in protein at ~200K. However, we have demonstrated that dry proteins also present a dynamical transition around 200 K if measured in the perdeuterated state by neutron scattering. This transition is absent in the dry hydrogenated protein due to the strong contribution of methyl rotations. Our results suggest that, as long as one can remove the contribution from methyl motions, the dynamical transition will be evident in the dry state. Using a neutron instrument with a low energy resolution such that methyl rotations cannot be resolved, e.g., ~100ueV, such as OSIRIS with PG004 reflection will assist us in analyzing the origin and influence of this dynamical transition in dry state.
DOI: 10.5286/isis.e.rb1810465
title: Frustrated Lewis pair encounter complexes in an ionic liquid

description: 'Frustrated Lewis Pairs' are believed to associate into an encounter complex held by dispersion forces, and that is it is this complex that interacts, and activates hydrogen, in a bi-molecular fashion. The formation of encounter complexes has been proposed by key theoretical evidence and computational studies, however experimental evidence to support their existence is very limited. In previous beam time, a direct experimental observation of the encounter complex between pairs of hindered Lewis acids and bases in a molecular solution was achieved. In this work, an ionic liquid solvent will be used to encourage the stability of the encounter complex, increasing its lifetime. In a molecular solvent, it is believed that 2 % of molecules exist as an encounter complex. greater proportion of encounter complexes would make their detection easier and modelling reveal more detail.
DOI: 10.5286/isis.e.rb1810571
title: Quantitative Benchmarks of state-of-art  Neutron Chemical Spectrometers - Part 1: TOSCA

description: We request 4 days on TOSCA to investigate the instrumental performance of the spectrometer, and to create from scratch an ad-hoc database for instrument-model validation.Two types of samples will be considered for measurements on TOSCA: zirconium hydride and polyethylene. Changing systematically sample amounts and thickness, signal-to-background ratio, LOD and LOQ, as well as the impact of multiple scattering (MP) will be addressed. Data will be manipulated and treated by chemometric techniques, starting with Principal Component Analysis (PCA), in order to assess instrumental resolution and accuracy. The data will also be used to perform the validation and preparation of TOSCA virtual model and virtual samples.
DOI: 10.5286/isis.e.rb1810790
title: A Study of Halogen Bonding in the Liquid State: Effect of Halogen Atom Substitution and Comparison to Hydrogen Bonding

description: Halogen bonding is a directional intermolecular interaction that occurs between covalently bonded halogens and Lewis bases. It is caused by the anisotropic distribution of charge around the halogen, being distributed radially around the bond axis, with a net positive charge opposite the R-X bond into which a Lewis base can donate its electron density. The past decade has seen an explosion of interest on the topic of halogen bonding, as this important intermolecular interaction is found in a number of applications including porous frameworks, liquid crystals, drug binding and organic catalysis. Measurements of liquid structure on a series of halo-pentafluorobenzene:pyridine mixtures will allow us to understand effect of the halogen substitution (Cl/Br/I) and compare to a similar hydrogen bonding system - pentafluorobenzene:pyridine.
DOI: 10.5286/isis.e.rb1720009
title: Field induced z=2 quantum critical dynamics in a 1d quantum magnet

description: Quantum phase transitions have recently received a lot of interest in various different fields of physics and the emergent universal properties have been studied in very different systems. Examples include 2D gases in semiconductor heterostructures, superfluid- or metal-insulator transitions, non-Fermi liquid behaviors or the condensation of quasi-particles in magnetic insulators. In our experiment we propose to study one particular field induced quantum critical point in a quasi-one-dimensional quantum magnet by means of inelastic neutron scattering. This will allow us to study in detail the dynamics in the quantum critical regime. (So far only static properties have been studied.) For the quantum critical point we will focus on, very strong theoretical predictions are available. Hence a quantitative comparison between experiment and theory will become possible.
DOI: 10.5286/isis.e.rb1720134
title: Variable Temperature Study of Structural Transitions Occurring In Clusters of Metal Organic Framework UiO-66

description: Catalysts lower energy costs of a wide range of important processes, from the production of oil and plastics to the preparation of drugs and paints, making these products affordable. The search for new catalysts is vital as they allow otherwise expensive if not impossible products to be made. Metal organic frameworks (MOFs) are modular compounds, the structures of which can be readily tuned for use as catalysts. UiO-66 has been of great interest and we have shown the use of the Ce(IV)-form in catalytic reactions. Activation of UiO-66 involves heating the MOF to high temperature to remove water (and hydroxyl groups) from the structure. However in UiO-66 compounds made with Zr(IV), this causes additional changes in the structure. We will systematically investigate how different metal compositions of the MOF influence these structural changes to optimise UiO-66 for catalytic applications.
DOI: 10.5286/isis.e.rb1720136
title: Spin Rotation Experiments at a Pulsed Muon Source using Broadband RF Pulses

description: In this proposal we wish to explore how the RF-MuSR technique might be developed for measurements akin to FT-NMR. Our work will focus on the broadband excitation of paramagnetic systems where a short, intense RF pulse excites a band of frequencies centred on the RF carrier that are measured simultaneously in the free precession signal. This continuation proposal will focus on the application of the technique to the measurement of free precession signals for muoniated radicals, using norbornene as a test system.
DOI: 10.5286/isis.e.rb1720153
title: Stroboscopic Neutron and X-ray mapping of strain fields in dynamically loaded engineering components

description: Bearings are essential components in many types of machinery, working to reduce energy losses. Over the last century improved analytical models were developed for predicting the operational lifetime of bearings, but still result in underestimated lifetimes. In the gearbox of a wind turbine, these premature bearing failures will happen with limited warning, causing significant periods of time when the turbine is non-operational. A testing rig has been designed to recreate conditions experienced by these gearbox bearings, whilst allowing for strain measurements using X-rays and neutron diffraction techniques. By collecting data specifically when the cycling stresses in the bearing raceway are at a maximum, it is possible to study the evolution of strain in the lead up to failure. The results will provide crucial information for developing commercial monitoring techniques used in industry
DOI: 10.5286/isis.e.rb1720203
title: Testing protein location in curved lipid bilayers using oriented lipid cubic phases

description: This proposal will test whether membrane proteins within lipid cubic phases preferentially sit in more or less curved bilayer regions, using our recent advances in preparing cubic phase films with high orientation, combined with 2D Grazing Incidence-SANS. This is a resubmission of previous ISIS proposal RB1710446, for which panel feedback was that it was highly rated, but evidence was requested for availability of the labelled protein OmpF. We now have an e-mail from our collaborators in Newcastle confirming that they will provide labelled and unlabelled OmpF.
DOI: 10.5286/isis.e.rb1720321
title: High energy spin excitations detwinned SrFe2As2 single crystals

description: We are proposing to use inelastic neutron scattering to map out the spin excitation in 100% detwinned SrFe2As2 single crystals. We want to sort out how the anisotropic magnetic excitation evolves and how it correlates to nematicity.
DOI: 10.5286/isis.e.rb1810410
title: Probing Interactions between Brønsted Acid sites and Phenolic Lignin Monomers for Model Development of Biomass Conversions in Zeolites

description: We propose to measure the vibrational spectra of phenolic lignin monomers phenol and catechol in zeolite Beta, in order to understand further the interactions of these important biomass building blocks with Brønsted Acid sites in promising catalysts for the conversion of biomass to valuable chemicals. Spectral shifting of vibrational bands of both the catalyst Brønsted acid sites and monomer OH groups will be of great value in parameterising classical simulationforcefields, particularly when combined with our DFT calculations, MD simulations and QENS experiments. We therefore aim to learn about important sorbate-catalyst interactions in these promising systems for sustainable chemicals production, while also using our observations to develop computational models of zeolite catalysed biomass conversions which are viable over the nanometre/nanosecond scale
DOI: 10.5286/isis.e.rb1810468
title: Hydrogenation of frustrated Lewis pairs in solution

description: It has been postulated that 'Frustrated Lewis Pairs' react after associating in an encounter complex held by dispersion forces, and that is it is this complex that interacts, and activates hydrogen, in a bi-molecular fashion. The formation of encounter complexes has been proposed by key theoretical evidence and computational studies, however experimental evidence to support their existence is very limited. In previous beam time a direct experimental observation of the encounter complex between pairs of hindered Lewis acids and bases in solution was achieved. In this work we hope to observe the heterolytic cleavage of hydrogen in solution using the system previously studied.
DOI: 10.5286/isis.e.rb1810559
title: Investigation of the nuclear and magnetic structures of GaV4S8-ySey materials

description: Skyrmions, nano-sized topological objects, have recently been found in GaV4S8 and GaV4Se8materials. In the search of new Skyrmion hosting materials, we have synthesised the GaV4S8-ySey (y = 0 to 8) family of materials. In contrasts to the long range ferromagnetic orderingexhibited by GaV4S8 and GaV4Se8, a canted antiferromagnetic state is found in materials with ybetween 2 and 6. Here we propose to investigate the nuclear and magnetic structures of GaV4S8,GaV4Se8 and GaV4S4Se4 samples with neutron diffraction in order to explore the drastic changein the observed magnetism in this family. We will be using both powder samples (GEM) andsingle crystals (SXD) for our investigations.
DOI: 10.5286/isis.e.rb1720322
title: Copy of: Field driven quantum phase transition in a Kitaev honeycomb magnet

description: The experimental realization of a Kitaev model on the honeycomb lattice has been a major topic in a condensed matter physics, because the model uniquely provides exactly solvable quantum spin liquid ground states in terms of fractionalized Majorana fermions. The alpha-RuCl3 forming a perfect honeycomb lattice with Ising-like spin-spin interaction has strong indications that it lies in proximate to a Kitaev spin liquid phase. Although the material exhibits antiferromagnetic ordering below 6.5 K, the hidden Kitaev physics in the ordered ground state is still ambiguous, and an external magnetic field can give a control parameter of addressing Kitaev Physics. We propose inelastic neutron scattering study on the alpha-RuCl3 single crystal to explore the magnetic field driven quantum phase transition.