Dynamics of hydrogen in Pr2Fe17H4 and Pr2Fe17H5 studied by quasielastic neutron scattering

E. Mamontov; T. J. Udovic; J. J. Rush; O. Isnard

doi:10.1016/j.jallcom.2005.11.064

Dynamics of hydrogen in Pr₂Fe₁₇H₄ and Pr₂Fe₁₇H₅ studied by quasielastic neutron scattering

E. Mamontov, T. J. Udovic, J. J. Rush, O. Isnard

Research output: Contribution to journal › Article › peer-review

7 Scopus citations

Abstract

Quasielastic neutron scattering (QENS) has been used to investigate the dynamics of hydrogen in Pr₂Fe₁₇H₄, where isolated hexagons formed by the interstitial tetrahedral (t) sites of the metal lattice host mobile hydrogen atoms (on average, one H atom per hexagon). An activation energy of 0.10 eV has been measured for a localized jump process involving the hopping of these hydrogen atoms among adjacent vertices of each hexagon. This activation energy is somewhat lower compared to that for hydrogen hopping in Pr₂Fe₁₇H₅, where each hexagon is occupied by two hydrogen atoms. The fraction of the hydrogen atoms immobilized on the t sites by defects in the host metal lattice is slightly higher in Pr₂Fe₁₇H₄ compared to Pr₂Fe₁₇H₅. These results are consistent with our earlier view of Pr₂Fe₁₇H₅ as a system where the hopping of the t-site hydrogen atoms occurs through the correlated jumps of the two H atoms occupying each isolated hexagon.

Original language	English
Pages (from-to)	149-152
Number of pages	4
Journal	Journal of Alloys and Compounds
Volume	422
Issue number	1-2
DOIs	https://doi.org/10.1016/j.jallcom.2005.11.064
State	Published - Sep 28 2006
Externally published	Yes

Funding

Utilization of the DAVE package [20] for the data analysis is acknowledged. This work utilized NIST facilities supported in part by the NSF under Agreement No. DMR-0454672.

Funders	Funder number
National Science Foundation

Keywords

Diffusion
Inelastic neutron scattering
Metal hydrides

Access to Document

10.1016/j.jallcom.2005.11.064

Cite this

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title = "Dynamics of hydrogen in Pr2Fe17H4 and Pr2Fe17H5 studied by quasielastic neutron scattering",

abstract = "Quasielastic neutron scattering (QENS) has been used to investigate the dynamics of hydrogen in Pr2Fe17H4, where isolated hexagons formed by the interstitial tetrahedral (t) sites of the metal lattice host mobile hydrogen atoms (on average, one H atom per hexagon). An activation energy of 0.10 eV has been measured for a localized jump process involving the hopping of these hydrogen atoms among adjacent vertices of each hexagon. This activation energy is somewhat lower compared to that for hydrogen hopping in Pr2Fe17H5, where each hexagon is occupied by two hydrogen atoms. The fraction of the hydrogen atoms immobilized on the t sites by defects in the host metal lattice is slightly higher in Pr2Fe17H4 compared to Pr2Fe17H5. These results are consistent with our earlier view of Pr2Fe17H5 as a system where the hopping of the t-site hydrogen atoms occurs through the correlated jumps of the two H atoms occupying each isolated hexagon.",

keywords = "Diffusion, Inelastic neutron scattering, Metal hydrides",

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T1 - Dynamics of hydrogen in Pr2Fe17H4 and Pr2Fe17H5 studied by quasielastic neutron scattering

AU - Mamontov, E.

AU - Udovic, T. J.

AU - Rush, J. J.

AU - Isnard, O.

PY - 2006/9/28

Y1 - 2006/9/28

N2 - Quasielastic neutron scattering (QENS) has been used to investigate the dynamics of hydrogen in Pr2Fe17H4, where isolated hexagons formed by the interstitial tetrahedral (t) sites of the metal lattice host mobile hydrogen atoms (on average, one H atom per hexagon). An activation energy of 0.10 eV has been measured for a localized jump process involving the hopping of these hydrogen atoms among adjacent vertices of each hexagon. This activation energy is somewhat lower compared to that for hydrogen hopping in Pr2Fe17H5, where each hexagon is occupied by two hydrogen atoms. The fraction of the hydrogen atoms immobilized on the t sites by defects in the host metal lattice is slightly higher in Pr2Fe17H4 compared to Pr2Fe17H5. These results are consistent with our earlier view of Pr2Fe17H5 as a system where the hopping of the t-site hydrogen atoms occurs through the correlated jumps of the two H atoms occupying each isolated hexagon.

AB - Quasielastic neutron scattering (QENS) has been used to investigate the dynamics of hydrogen in Pr2Fe17H4, where isolated hexagons formed by the interstitial tetrahedral (t) sites of the metal lattice host mobile hydrogen atoms (on average, one H atom per hexagon). An activation energy of 0.10 eV has been measured for a localized jump process involving the hopping of these hydrogen atoms among adjacent vertices of each hexagon. This activation energy is somewhat lower compared to that for hydrogen hopping in Pr2Fe17H5, where each hexagon is occupied by two hydrogen atoms. The fraction of the hydrogen atoms immobilized on the t sites by defects in the host metal lattice is slightly higher in Pr2Fe17H4 compared to Pr2Fe17H5. These results are consistent with our earlier view of Pr2Fe17H5 as a system where the hopping of the t-site hydrogen atoms occurs through the correlated jumps of the two H atoms occupying each isolated hexagon.

KW - Diffusion

KW - Inelastic neutron scattering

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