Estimates of Quantum Tunneling Effects for Hydrogen Diffusion in PuO<sub>2</sub>

We detail the estimation of activation energies and quantum nuclear vibrational tunneling effects for hydrogen diffusion in PuO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><m...

Full description

Bibliographic Details
Main Authors: Nir Goldman, Luis Zepeda-Ruiz, Ryan G. Mullen, Rebecca K. Lindsey, C. Huy Pham, Laurence E. Fried, Jonathan L. Belof
Format: Article
Language:English
Published: MDPI AG 2022-10-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/12/21/11005
_version_ 1797469188265082880
author Nir Goldman
Luis Zepeda-Ruiz
Ryan G. Mullen
Rebecca K. Lindsey
C. Huy Pham
Laurence E. Fried
Jonathan L. Belof
author_facet Nir Goldman
Luis Zepeda-Ruiz
Ryan G. Mullen
Rebecca K. Lindsey
C. Huy Pham
Laurence E. Fried
Jonathan L. Belof
author_sort Nir Goldman
collection DOAJ
description We detail the estimation of activation energies and quantum nuclear vibrational tunneling effects for hydrogen diffusion in PuO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> based on Density Functional Theory calculations and a quantum double well approximation. We find that results are relatively insensitive to choice of exchange correlation functional. In addition, the representation of spin in the system and use of an extended Hubbard U correction has only a small effect on hydrogen point defect formation energies when the PuO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> lattice is held fixed at the experimental density. We then compute approximate activation energies for transitions between hydrogen interstitial sites seeded by a semi-empirical quantum model and determine the quantum tunneling enhancement relative to classical kinetic rates. Our model indicates that diffusion rates in H/PuO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> systems could be enhanced by more than one order of magnitude at ambient conditions and that these effects persist at high temperature. The method we propose here can be used as a fast screening tool for assessing possible quantum nuclear vibrational effects in any number of condensed phase materials and surfaces, where hydrogen hopping tends to follow well defined minimum energy pathways.
first_indexed 2024-03-09T19:17:54Z
format Article
id doaj.art-360f091790d344c8a3fbb8c1407cee97
institution Directory Open Access Journal
issn 2076-3417
language English
last_indexed 2024-03-09T19:17:54Z
publishDate 2022-10-01
publisher MDPI AG
record_format Article
series Applied Sciences
spelling doaj.art-360f091790d344c8a3fbb8c1407cee972023-11-24T03:36:26ZengMDPI AGApplied Sciences2076-34172022-10-0112211100510.3390/app122111005Estimates of Quantum Tunneling Effects for Hydrogen Diffusion in PuO<sub>2</sub>Nir Goldman0Luis Zepeda-Ruiz1Ryan G. Mullen2Rebecca K. Lindsey3C. Huy Pham4Laurence E. Fried5Jonathan L. Belof6Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USAPhysical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USAPhysical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USADepartment of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USAPhysical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USAPhysical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USAPhysical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USAWe detail the estimation of activation energies and quantum nuclear vibrational tunneling effects for hydrogen diffusion in PuO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> based on Density Functional Theory calculations and a quantum double well approximation. We find that results are relatively insensitive to choice of exchange correlation functional. In addition, the representation of spin in the system and use of an extended Hubbard U correction has only a small effect on hydrogen point defect formation energies when the PuO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> lattice is held fixed at the experimental density. We then compute approximate activation energies for transitions between hydrogen interstitial sites seeded by a semi-empirical quantum model and determine the quantum tunneling enhancement relative to classical kinetic rates. Our model indicates that diffusion rates in H/PuO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> systems could be enhanced by more than one order of magnitude at ambient conditions and that these effects persist at high temperature. The method we propose here can be used as a fast screening tool for assessing possible quantum nuclear vibrational effects in any number of condensed phase materials and surfaces, where hydrogen hopping tends to follow well defined minimum energy pathways.https://www.mdpi.com/2076-3417/12/21/11005plutonium oxideDensity Functional Theoryhydrogen diffusionquantum tunneling effects
spellingShingle Nir Goldman
Luis Zepeda-Ruiz
Ryan G. Mullen
Rebecca K. Lindsey
C. Huy Pham
Laurence E. Fried
Jonathan L. Belof
Estimates of Quantum Tunneling Effects for Hydrogen Diffusion in PuO<sub>2</sub>
Applied Sciences
plutonium oxide
Density Functional Theory
hydrogen diffusion
quantum tunneling effects
title Estimates of Quantum Tunneling Effects for Hydrogen Diffusion in PuO<sub>2</sub>
title_full Estimates of Quantum Tunneling Effects for Hydrogen Diffusion in PuO<sub>2</sub>
title_fullStr Estimates of Quantum Tunneling Effects for Hydrogen Diffusion in PuO<sub>2</sub>
title_full_unstemmed Estimates of Quantum Tunneling Effects for Hydrogen Diffusion in PuO<sub>2</sub>
title_short Estimates of Quantum Tunneling Effects for Hydrogen Diffusion in PuO<sub>2</sub>
title_sort estimates of quantum tunneling effects for hydrogen diffusion in puo sub 2 sub
topic plutonium oxide
Density Functional Theory
hydrogen diffusion
quantum tunneling effects
url https://www.mdpi.com/2076-3417/12/21/11005
work_keys_str_mv AT nirgoldman estimatesofquantumtunnelingeffectsforhydrogendiffusioninpuosub2sub
AT luiszepedaruiz estimatesofquantumtunnelingeffectsforhydrogendiffusioninpuosub2sub
AT ryangmullen estimatesofquantumtunnelingeffectsforhydrogendiffusioninpuosub2sub
AT rebeccaklindsey estimatesofquantumtunnelingeffectsforhydrogendiffusioninpuosub2sub
AT chuypham estimatesofquantumtunnelingeffectsforhydrogendiffusioninpuosub2sub
AT laurenceefried estimatesofquantumtunnelingeffectsforhydrogendiffusioninpuosub2sub
AT jonathanlbelof estimatesofquantumtunnelingeffectsforhydrogendiffusioninpuosub2sub