Hydrogen gas sample environment for TOSCA

Kibble, Mark; Ramirez‐Cuesta, Anibal J.; Goodway, Chris; Evans, Beth; Kirichek, O.

doi:10.1088/1742-6596/554/1/012006

Cited by 7 publications

(5 citation statements)

References 9 publications

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“…The sample, H2 or D2, was condensed into a thin-walled aluminium can with a path length of 1 mm. Parahydrogen was prepared in an apparatus that has been previously described [13].…”

Section: Methodsmentioning

confidence: 99%

Observation of the stretch mode in H₂ and D₂ by inelastic neutron scattering spectroscopy

Parker

Ewings

Fernandez-Alonso

et al. 2018

J. Phys.: Conf. Ser.

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Abstract. The interaction of H2 with materials is relevant to areas such as catalysis, hydrogen storage and fuel cells. Inelastic neutron scattering has been extensively used for such studies, which have generally utilised the J 01 rotational line at 14.5 meV of parahydrogen. Unfortunately, this is very difficult to model. The problem would be mitigated by studying the fundamental H-H stretch vibration at 516 meV, because the calculation becomes a conventional lattice dynamics problem, which is tractable with density functional theory. Here, we have chosen to investigate solid and liquid H2 and D2 as a test of whether it is possible to observe the H-H and D-D stretch. This is only possible with a direct geometry spectrometer at a spallation neutron source, since only this combination of facilities gives access to high energy neutrons with a wide range of momentum transfer. The measurements were successful and, in addition to several rotational states of the ground vibrational state, a feature recoiling from an origin value of 516 meV for H2 and from 370 meV for D2 is observed in both the solid and liquid states. These are assigned to the H-H and D-D stretch respectively. IntroductionThe study of molecular hydrogen (H2, dihydrogen) in, or on, materials is relevant to areas such as catalysis [1], hydrogen storage [2] and fuel cells [3]. Inelastic neutron scattering (INS) is well-suited to studies of such systems because the large 1 H cross section and the transparency of most materials to neutrons means that most of the information obtained directly relates to the adsorbed dihydrogen. These studies are almost invariably carried out with the J 01 rotational line at 14.5 meV of parahydrogen as the probe of choice [4]. The reasons for this are that not only its transition energy [4] but also its underlying line shape [5,6] are sensitive probes of the local environment and the instruments generally have their best resolution in this energy region.The disadvantage of studying the rotational transition is that it is very difficult to model. This has been done with either a phenomenological model of how the rotational energy levels behave in an applied potential [4] or have required very sophisticated multi-dimensional ab initio calculations [7]. These difficulties could be reduced by studying the fundamental H-H stretch vibration at 516 meV, because the calculation is now a conventional lattice dynamics problem, which is tractable with density functional theory [8].

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“…The sample, H2 or D2, was condensed into a thin-walled aluminium can with a path length of 1 mm. Parahydrogen was prepared in an apparatus that has been previously described [13].…”

Section: Methodsmentioning

confidence: 99%

Observation of the stretch mode in H₂ and D₂ by inelastic neutron scattering spectroscopy

Parker

Ewings

Fernandez-Alonso

et al. 2018

J. Phys.: Conf. Ser.

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“…Alongside, instrument developments at neutron sources have continued to support these research programmes, including: (i) a new Target-Station 2 (TS2) at ISIS, which has considerably improved the flux on TOSCA at low-energies; (ii) developments in sample environment equipment, including advanced gas-handling capabilities (see, e.g., Ref. [ 259 ]); (iii) ongoing developments in indirect-geometry instruments, reducing the requisite sample quantities considerably [ 137 , 138 , 139 , 140 , 141 ]; (iv) the commissioning of new instruments, like VISION at the SNS and LAGRANGE at the ILL [ 143 ], or the design of VESPA for the ESS [ 1 ]; and (v) progress in the field of ab initio modeling and its integration with experiments—as shown in Table 1 , we underline the substantial increase over time in the number of publications using solid-state DFT. Altogether, these have enabled the study of the vibrational dynamics over a wide energy-transfer range and, more importantly, to place a fresh focus on the structural properties and flexibility of these soft materials, key to understand their rich polymorphism and sorption behavior [ 74 , 260 ].…”

Section: From Confined Polymers To Soft Supramolecular Frameworkmentioning

confidence: 99%

Dynamics & Spectroscopy with Neutrons—Recent Developments & Emerging Opportunities

2021

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This work provides an up-to-date overview of recent developments in neutron spectroscopic techniques and associated computational tools to interrogate the structural properties and dynamical behavior of complex and disordered materials, with a focus on those of a soft and polymeric nature. These have and continue to pave the way for new scientific opportunities simply thought unthinkable not so long ago, and have particularly benefited from advances in high-resolution, broadband techniques spanning energy transfers from the meV to the eV. Topical areas include the identification and robust assignment of low-energy modes underpinning functionality in soft solids and supramolecular frameworks, or the quantification in the laboratory of hitherto unexplored nuclear quantum effects dictating thermodynamic properties. In addition to novel classes of materials, we also discuss recent discoveries around water and its phase diagram, which continue to surprise us. All throughout, emphasis is placed on linking these ongoing and exciting experimental and computational developments to specific scientific questions in the context of the discovery of new materials for sustainable technologies.

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“…In cases where higher temperatures or pressures are required cells made from TAV6 and/or TiZr material may be preferable. We also included for comparison a spectrum of the high-pressure cell made of TiZr in CuBe sleeve already used in TOSCA experiments [7].…”

Section: Collected Neutron Datamentioning

confidence: 99%

“…Consequently, high pressure can only be obtained by applying large forces which implies massive mechanical devices. As a result, the main difficulty encountered in inelastic neutron scattering experiments is the issue of the neutron beam having to travel through rather thick sections of the pressure vessels which contain the sample under investigation [5,7]. This gives rise to unwanted absorption and coherent or incoherent background scattering which can be mitigated by the right choice of vessel material and the optimisation of a high-pressure vessel geometry design [8,18].…”

Section: Introductionmentioning

confidence: 99%

Low-background materials for high pressure cells used in inelastic neutron scattering experiments

Kibble

Laliena

Goodway

et al. 2020

JNR

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The signal-to-noise ratio is the ultimate limiting factor for high pressure neutron scattering experiments where sample environment equipment could create significant background signal which in many cases may significantly exceed the signal from the sample itself. This is the particularly serious issue in case of high-pressure sample environment for inelastic neutron scattering. Here we review materials which could be used for development of new generation of high-pressure cells for inelastic and quasi-elastic neutron scattering experiments. We also present results of modelling of the background of high-pressure vessels made out of different materials. This approach will allow designing and producing high pressure vessels with parameters desired for particular neutron scattering experiment.

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Hydrogen gas sample environment for TOSCA

Cited by 7 publications

References 9 publications

Observation of the stretch mode in H₂ and D₂ by inelastic neutron scattering spectroscopy

Observation of the stretch mode in H₂ and D₂ by inelastic neutron scattering spectroscopy

Dynamics & Spectroscopy with Neutrons—Recent Developments & Emerging Opportunities

Low-background materials for high pressure cells used in inelastic neutron scattering experiments

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Hydrogen gas sample environment for TOSCA

Cited by 7 publications

References 9 publications

Observation of the stretch mode in H2 and D2 by inelastic neutron scattering spectroscopy

Observation of the stretch mode in H2 and D2 by inelastic neutron scattering spectroscopy

Dynamics & Spectroscopy with Neutrons—Recent Developments & Emerging Opportunities

Low-background materials for high pressure cells used in inelastic neutron scattering experiments

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Product

Resources

About

Observation of the stretch mode in H₂ and D₂ by inelastic neutron scattering spectroscopy

Observation of the stretch mode in H₂ and D₂ by inelastic neutron scattering spectroscopy