A5042576741- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Quantum, superfluid, helium dynamics
- High-pressure geophysics and materials
- Solid-state spectroscopy and crystallography
- Material Dynamics and Properties
- Radiation Detection and Scintillator Technologies
- Advanced NMR Techniques and Applications
- Advanced Chemical Physics Studies
- Perovskite Materials and Applications
- Graphene research and applications
- Spectroscopy and Quantum Chemical Studies
- Magnetism in coordination complexes
- Advanced Condensed Matter Physics
- X-ray Diffraction in Crystallography
- Nuclear reactor physics and engineering
- Carbon Nanotubes in Composites
- Hydrogen Storage and Materials
- Spectroscopy and Laser Applications
- Phase Equilibria and Thermodynamics
- Crystallography and molecular interactions
- Crystallization and Solubility Studies
- Lanthanide and Transition Metal Complexes
- Organic and Molecular Conductors Research
- Advanced Chemical Sensor Technologies
Donostia International Physics Center
2020-2024
Ikerbasque
2019-2024
Material Physics Center
2022-2024
University College London
2014-2023
Rutherford Appleton Laboratory
2011-2020
European Spallation Source
2020
Technical University of Denmark
2020
Science and Technology Facilities Council
2018-2020
Oxfam
2016-2019
Didcot Community Hospital
2015-2017
We present an unambiguous identification of low-frequency terahertz vibrations in the archetypal imidazole-based metal-organic framework (MOF) materials: ZIF-4, ZIF-7, and ZIF-8, all which adopt a zeolite-like nanoporous structure. Using inelastic neutron scattering synchrotron radiation far-infrared absorption spectroscopy, conjunction with density functional theory (DFT), we have pinpointed major sources vibrational modes. Ab initio DFT calculations revealed complex nature collective THz...
The accurate description of van der Waals forces within density functional theory is currently one the most active areas research in computational physics and chemistry. Here we report results on structural energetic properties graphite hexagonal boron nitride, two layered materials where interlayer binding dominated by forces. Results from several functionals are reported, including optimized Becke88 (optB88-vdW) PBE (optPBE-vdW) (Klimeš et al 2010 J. Phys.: Condens. Matter 22 022201)...
TOSCA is a high-resolution neutron spectrometer at the ISIS Pulsed Neutron and Muon Source.The instrument optimised for broadband vibrational spectroscopy in 0 -4000 cm -1 region it has been operational since 2000.This paper describes how progressively upgraded intervening years to enable new science.Future upgrades are outlined.
This work provides an up-to-date account of the use electron-volt neutron spectroscopy in materials research. is a growing area science, capitalising upon unique insights provided by epithermal neutrons on behaviour and properties increasing number complex materials. As such, present builds aims scope previous contribution to this journal back 2005, whose primary focus was detailed description theoretical foundations technique their application fundamental systems [see Andreani et al., Adv....
Recent studies of state-resolved angular distributions show the participation reactive scattering resonances in simplest chemical reaction. This review is intended for those who wish to learn about state-of-the-art study H + H2 reaction family that has made this breakthrough possible. also gain insight into nature resonances. Following a tour across several fields physics and chemistry where concept resonance been crucial understanding new phenomena, we offer an operational definition...
We show clear experimental evidence of cooperative terahertz (THz) dynamics observed below 3 THz ($\ensuremath{\sim}100\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}1}$), for a low-symmetry Zr-based metal-organic framework structure, termed MIL--140A [$\mathrm{ZrO}({\mathrm{O}}_{2}{\mathrm{C}\text{\ensuremath{-}}\mathrm{C}}_{6}{\mathrm{H}}_{4}\text{\ensuremath{-}}{\mathrm{CO}}_{2})$]. Utilizing combination high-resolution inelastic neutron scattering and synchrotron radiation far-infrared...
Single-site Au species supported on carbon have been shown to be the active sites for acetylene hydrochlorination. The evolution of these single-site has monitored by L3 X-ray absorption spectroscopy (XAS). Alternating between a standard reaction mixture HCl/C2H2 and single reactants provided insights into mechanism catalyst deactivation processes. We demonstrate that oxidative addition HCl across an Au(I) chloride requires concerted with C2H2, in accordance both XAS measurements oxidation...
High-resolution inelastic neutron scattering and extensive first-principles calculations have been used to explore the low-temperature phase of hybrid solar-cell material methylammonium lead iodide up well-known transition tetragonal at ca. 160 K. Contrary original expectation, we find that Pnma structure for this can only provide a qualitative description geometry underlying motions organic cation. A substantial lowering local symmetry inside perovskite cage leads an improved atomistic...
We have investigated the noncentrosymmetric tetragonal heavy-fermion antiferromagnetic compound CeCuAl3 (T(N)=2.5 K) using inelastic neutron scattering (INS). Our INS results unequivocally reveal presence of three magnetic excitations centered at 1.3, 9.8, and 20.5 meV. These spectral features cannot be explained within framework crystal-electric-field models recourse to Kramers' theorem for a 4f(1) Ce(3+) ion. To overcome these interpretational difficulties, we generalized vibron model...
The VESUVIO spectrometer at the ISIS pulsed neutron and muon source is a unique instrument amongst those available facilities. This only inverted-geometry accessing values of energy wavevector transfer above tens eV ${\mathring{\rm A}}^{-1}$ , respectively, where deep inelastic scattering experiments are routinely performed. As such, procedure base technique has been previously described in an article published by this journal (Mayers Reiter 2012 Meas. Sci. Technol. 23 045902). recently...
Reactions between Co(OAc)2 and 2-amino-2-methyl-1,3-propanediol (ampdH2) afford a hexanuclear complex [Co6(H2O)(MeOH)(OAc)6(ampd)4] (1) one-dimensional coordination polymer comprised of discrete heptanuclear complexes covalently bound to mononuclear Co centers [Co8(H2O)2(OAc)7(ampd)6]n (2). While 1 is obtained under ambient reaction conditions, the formation 2 requires solvothermal methods. Both products have been characterized crystallographically found be mixed-valent, containing divalent...
The effects of confining molecular hydrogen within carbon nanohorns are studied via high-resolution quasielastic and inelastic neutron spectroscopies. Both sets data remarkably different from those obtained in bulk samples the liquid crystalline states. At temperatures where is liquid, spectra confined sample show an elastic component indicating a significant proportion immobile molecules as well distinctly narrower line widths strong distortion shape para-->ortho rotational transition....
Abstract The reaction of N ‐(2‐hydroxy‐5‐nitrobenzyl)iminodiethanol (=H 3 (5‐NO 2 ‐hbide)) with Mn(OAc) ⋅ 4 H O in methanol, followed by recrystallization from 1,2‐dichloroethane, yielded a wheel‐shaped single‐molecule magnet (SMM) [Mn II Mn III ‐hbide) 6 ]⋅5 C Cl ( 1 ). In , seven manganese ions are linked six tri‐anionic ligands and form the wheel which two on rim one center other four ions. Powder magnetic susceptibility measurements showed gradual increase χ m T values as temperature was...
Both structural glasses and disordered crystals are known to exhibit anomalous thermal, vibrational, acoustic properties at low temperatures or energies, what is still a matter of lively debate. To shed light on this issue, we studied the halomethane family ${\mathrm{CBr}}_{n}{\mathrm{Cl}}_{4\ensuremath{-}n}$ ($n=0,1,2$) temperature where, despite being perfectly translationally ordered stable monoclinic crystals, glassy dynamical features had been reported from experiments molecular...
We have investigated the P–T phase diagram of ammonia dihydrate (ADH), ND3·2D2O, using powder neutron diffraction methods over range 0–9 GPa, 170–300 K. In addition to ambient pressure phase, ADH I, we identified three high-pressure phases, II, III, and IV, each which has been reproduced in at least separate experiments. Another, apparently body-centred-cubic, observed on a single occasion above 6 GPa 170 The existence dehydration boundary confirmed where, upon compression or warming, IV...
The confinement of poly(ethylene oxide) in graphite oxide is studied using a combination diffraction, calorimetric, and spectroscopic methods. Polymer intercalation into subnanometer layers leads to the complete suppression crystallization phenomena dielectric α-relaxation processes, as well slowdown β-relaxation modes. For first time, high-resolution inelastic neutron scattering shows that under these extreme conditions adopts planar zig-zag conformation, no way resembling characteristic 72...
We explore the effects of chain size on structure and dynamics ethylene glycol (EG) poly(ethylene oxide) (PEO) intercalated in graphite oxide (GO). To this end, EG as well a PEO series increasing length have been studied by means high-resolution inelastic neutron spectroscopy. The experiments are complemented X-ray diffraction, differential scanning calorimetry, Fourier-transform infrared spectroscopy, Raman scattering. find that is accommodated layer thickness ∼3 Å within GO substrate...
In this work, high-resolution inelastic neutron scattering (INS) has been used to provide novel insights into the properties of confined poly(ethylene oxide) (PEO) chains. Two limits have explored in detail, namely, single-layer 2D-polymer intercalation graphite oxide (GO) and surface polymer adsorption onto thermally reduced exfoliated oxide, that is, graphene (G) sheets. Careful control over degree GO oxidation exfoliation reveals three distinct cases spatial confinement: (i) subnanometer...
We apply a unique sequence of structural and dynamical neutron-scattering techniques, augmented with density-functional electronic-structure calculations, to establish the degree polymorphism in an archetypal hydrogen-bonded system - crystalline formic acid. Using this combination experimental theoretical hypothesis by Zelsmann on coexistence β1 β2 phases above 220 K is tested. Contrary postulated scenario proton-transfer-driven phase coexistence, emerging picture one quantitatively...
Neutron spectroscopy and first-principles calculations unveil the quantum character of atomic motions in solid acid CsHSO<sub>4</sub>.