The neutron guide upgrade of the TOSCA spectrometer

Pinna, Roberto S.; Rudić, Svemir; Parker, Stewart F.; Armstrong, Jeff; Zanetti, Matteo; Škoro, G.; Waller, S.; Zacek, D.; Smith, C.; Capstick, Matthew J.; McPhail, D.; Pooley, Daniel E.; Howells, Gareth D.; Gorini, G.; Fernandez-Alonso, Félix

doi:10.1016/j.nima.2018.04.009

Cited by 91 publications

(91 citation statements)

References 9 publications

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“…The experimental high-resolution vibrational neutron spectroscopy, INS, was carried out at the ISIS Pulsed Neutron and Muon source on the inverted-geometry TOSCA instrument at ≈10 K in a closed-cycle helium refrigerator [18][19][20][21]. A 5 g powder sample was measured in a flat aluminium cell with 4×4.8 cm 2 cross-section area.…”

Section: Methodsmentioning

confidence: 99%

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La₂LiHO₃ oxyhydride

et al. 2019

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Kobayashi et al (6279) (Science 2016, 351) reported recently the existence of pure Hconductivity in the oxyhydride La 2−x−y Sr x+y LiH 1−x+y O 3−y , while demonstrating its functionality through a prototype solid-state Ti/La 2 LiHO 3 /TiH 2 battery. In this study, we probe the atomistic motion of La 2 LiHO 3 obtained by the promising halide salt flux method, via a combination of deep inelastic neutron scattering (DINS) and ab initio lattice dynamics (LD) calculations verified by vibrational inelastic neutron spectroscopy (INS). We successfully describe the measured momentum distributions from DINS via our LD calculations, without observing any diffusion activation over the temperature range reported by Kobayashi et al. This observation is corroborated by model predictions from our LD study, which reveals that the hydride anions remain bound within a 3D-harmonic potential. We conclude that with the current synthesis parameters, the method produces a vacancy free lattice, and that a necessary ingredient for diffusive motion of His the presence of a large population of vacancies. Based on the harmonic prediction for the hydrogen kinetic energy, we derive a picture of the evolution of the effective bonding potential for the hydride anions, and link this to the dynamics associated with decomposition of the oxyhydride.

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Section: Methodsmentioning

confidence: 99%

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La₂LiHO₃ oxyhydride

et al. 2019

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“…TOSCA is an time-offlight, indirect geometry, high resolution INS spectrometer. With the analyser-detector modules in both forward and back scattering mode, TOSCA is one of the best high resolution crystal analyser INS spectrometer in the world [14] having energy resolution ΔE/E<1% and energy transfer range up to 8000 cm −1 .…”

Section: Methodsmentioning

confidence: 99%

Identification of normal modes responsible for ferroelectric properties in organic ferroelectric CBDC

Mukhopadhyay

2019

J. Phys. Commun.

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Structure and dynamics of hydrogen bonded organic ferroelectric CBDC (1-cyclobutene-1,2dicarboxylic acid, C 6 H 8 O 4 ) have been investigated using inelastic neutron scattering (INS) spectroscopy and first principles lattice dynamics. Vibrational modes of O-H-O bending, related with two different types of hydrogen bonds, inter and intra-molecular, are manifested as two sets of doublets in the range of 900-1400 cm −1 in the INS spectrum. First principles density functional theory (DFT) is used to assign these doublets to out-of-the-plane and in-plane vibrations of these two types of O-H-O bending modes. Correlating structure and dynamics we find that although the local structures of the hydrogen bonded protons are similar, their medium range order may influence their vibrational frequencies. Vibrational modes of non-hydrogen bonded protons also are assigned separately in the spectrum. Comparing the calculated and the experimental INS spectra it is predicted that hydrogen bonded O-H bonds are more anharmonic than non-hydrogen bonded C-H bonds. From the calculated Born effective charge tensor it is predicted that inter-molecular hydrogen bonds contribute more to the ferroelectric polarisation of CBDC than intra-molecular ones. A large LO-TO splitting of the O-H stretching mode at 2471 cm −1 is identified with the mode that has significant contribution to the ferroelectric polarisation. As this mode is sensitive to long range Coulomb interactions and is responsible for ferroelectric properties of the material, vibrational spectroscopy combined with DFT calculations is proposed as a characterisation tool to investigate ferroelectric properties in the CBDC molecular crystal.

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Section: Introductionmentioning

confidence: 99%

“…120 and 176 cm −1 ) by combining INS with the deuteration of hydroxyl groups in the non-crystalline regions of native cellulose [38]. Further down the road, Araujo et al [39] explored the dynamics of hydrogen bonds in cellulose samples from distinct sources, namely microcrystalline cellulose, cotton cellulose, kraft pulp cellulose and BC, by INS (with the help of the TOSCA spectrometer) [40][41][42][43] and were able to easily distinguish between the crystalline forms of I α and I β allomorphs in the 700−800 cm −1 region. Moreover, this study set the stage for the future use of this technique to characterize BC-based materials, and in particular of nanocomposites [39].Under these premises and following our interest in the design and characterization of advanced and multifunctional BC-based nanocomposites [11,13,24], the present work intends to study the dynamics of hydrogen-bond networks in BC-based nanocomposites containing poly(2-hydroxyethyl methacrylate) (PHEMA), poly(methacroylcholine chloride) (PMACC) and poly(methacroylcholine hydroxide) (PMACH) by INS spectroscopy.…”

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Understanding the Structure and Dynamics of Nanocellulose-Based Composites with Neutral and Ionic Poly(methacrylate) Derivatives Using Inelastic Neutron Scattering and DFT Calculations

et al. 2020

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Bacterial nanocellulose (BC)-based composites containing poly(2-hydroxyethyl methacrylate) (PHEMA), poly(methacroylcholine chloride) (PMACC) or poly(methacroylcholine hydroxide) (PMACH) were characterized by inelastic neutron scattering (INS) spectroscopy, combined with DFT (density functional theory) calculations of model systems. A reasonable match between calculated and experimental spectral lines and their intensities was used to support the vibrational assignment of the observed bands and to validate the possible structures. The differences between the spectra of the nanocomposites and the pure precursors indicate that interactions between the components are stronger for the ionic poly(methacrylate) derivatives than for the neutral counterpart. Displaced anions interact differently with cellulose chains, due to the different ability to compete with the O-H···O hydrogen bonds in cellulose. Hence, the INS is an adequate technique to delve deeper into the structure and dynamics of nanocellulose-based composites, confirming that they are true nanocomposite materials instead of simple mixtures of totally independent domains. Keywords: bacterial nanocellulose; nanocomposites; poly(2-hydroxyethyl methacrylate); poly(methacroylcholine chloride); poly(methacroylcholine hydroxide); inelastic neutron scattering; DFT calculations IntroductionA tour through the kaleidoscopic portfolio of materials developed in the last decades, clearly shows that composite materials based on cellulose [1], and bacterial nanocellulose (BC) in particular [2], are quite relevant for myriad domains of applications [3][4][5]. In fact, the exopolysaccharide BC, which is biosynthesized by several non-pathogenic bacteria in the form of membranes with a tree-dimensional network of cellulose nanofibrils [6], has shown potential for drug delivery [7-9], wound healing [10,11], bone tissue engineering [12], antimicrobial materials [13], food and food packaging [14,15], water remediation [16,17] and fuel cells [5,18,19], just to mention some fields of application.In terms of production, BC-based nanocomposites can be prepared by in situ and ex situ methodologies [20], which already enabled the combination of BC with a vast array of synthetic polymers Molecules 2020, 25, 1689 2 of 16 (e.g., polyaniline [21] and Nafion [22]) and biopolymers (e.g., lactoferrin [23] and fucoidan [24]), as well as hybrid materials with metal oxides, metal sulphides and metal nanoparticles [4], and graphene and derivatives [25,26], with the aim of enhancing or adding novel properties to the ensuing materials [2]. Among the available methodologies, the in situ polymerization of monomers with, for instance, (metha)acrylate functional groups, is a simple top-down method that promotes the use of BC without altering its valuable and unique three-dimensional structure [2]. Acrylamide [27], acrylic acid [28], glyceryl monomethacrylate [29], 2-ethoxyethyl methacrylate [29], 2-aminoethyl methacrylate [30], methacryloyloxyethyl phosphate [31], N-methacryloyl glycine [7] and bis[2-(me...

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The neutron guide upgrade of the TOSCA spectrometer

Abstract: Citation: RS Pinna et al. "The neutron guide upgrade of the TOSCA spectrometer."

Cited by 91 publications

References 9 publications

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La₂LiHO₃ oxyhydride

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La₂LiHO₃ oxyhydride

Identification of normal modes responsible for ferroelectric properties in organic ferroelectric CBDC

Understanding the Structure and Dynamics of Nanocellulose-Based Composites with Neutral and Ionic Poly(methacrylate) Derivatives Using Inelastic Neutron Scattering and DFT Calculations

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The neutron guide upgrade of the TOSCA spectrometer

Abstract: Citation: RS Pinna et al. "The neutron guide upgrade of the TOSCA spectrometer."

Cited by 91 publications

References 9 publications

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La2LiHO3 oxyhydride

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La2LiHO3 oxyhydride

Identification of normal modes responsible for ferroelectric properties in organic ferroelectric CBDC

Understanding the Structure and Dynamics of Nanocellulose-Based Composites with Neutral and Ionic Poly(methacrylate) Derivatives Using Inelastic Neutron Scattering and DFT Calculations

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A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La₂LiHO₃ oxyhydride

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La₂LiHO₃ oxyhydride