Study of anharmonicity in zirconium hydrides using inelastic neutron scattering and ab-initio computer modeling

Jiayong Zhang, Yongqiang Cheng, Alexander I. Kolesnikov, Jerry Bernholc, Wenchang Lu, Anibal J. Ramirez-Cuesta

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

The anharmonic phonon behavior in zirconium hydrides and deuterides, including ɛ-ZrH2, γ-ZrH, and γ-ZrD, has been investigated from aspects of inelastic neutron scattering (INS) and lattice dynamics calculations within the framework of density functional theory (DFT). The harmonic model failed to reproduce the spectral features observed in the experimental data, indicating the existence of anharmonicity in those materials and the necessity of further explanations. Here, we present a detailed study on the anharmonicity in zirconium hydrides/deuterides by exploring the 2D potential energy surface of hydrogen/deuterium atoms and solving the corresponding 2D single-particle Schrödinger equation to obtain the eigenfrequencies, which are then convoluted with the instrument resolution. The convoluted INS spectra qualitatively describe the anharmonic peaks in the experimental INS spectra and demonstrate that the anharmonicity originates from the deviations of hydrogen potentials from quadratic behavior in certain directions; the effects are apparent for the higher-order excited vibrational states, but small for the ground and first excited states.

Original languageEnglish
Article number29
JournalInorganics
Volume9
Issue number5
DOIs
StatePublished - 2021

Funding

Funding: This work was supported through Oak Ridge National Laboratory’s Graduate Opportunity (Go!) Program in the Neutron Scattering Division, ORNL. Neutron scattering experiments were conducted at the VISION beamline at ORNL’s Spallation Neutron Source, which is supported by the Scientific User Facilities Division, Office of Basic Energy Sciences (BES), U.S. Department of Energy (DOE), under Contract No. DE-AC0500OR22725 with UT Battelle, LLC. The computing resources were made available through the VirtuES and the ICEMAN projects, funded by the Laboratory Directed Research and Development program at ORNL.

FundersFunder number
Scientific User Facilities Division
U.S. Department of EnergyDE-AC0500OR22725
Basic Energy Sciences
Oak Ridge National Laboratory
Laboratory Directed Research and Development

    Keywords

    • Anharmonicity
    • Density functional theory
    • Inelastic neutron scattering
    • Zirconium hydrides

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