Calculations of free energy barriers for local mechanisms of hydrogen diffusion in alanates

Michele Monteferrante; Sara Bonella; Simone Meloni; Eric Vanden-Eijnden; Giovanni Ciccotti

doi:10.1007/s10820-008-9097-x

Calculations of free energy barriers for local mechanisms of hydrogen diffusion in alanates

Michele Monteferrante, Sara Bonella, Simone Meloni, Eric Vanden-Eijnden, Giovanni Ciccotti

Mathematics

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

Abstract

Brute force histogram calculation and a recently developed method to efficiently reconstruct the free energy profile of complex systems (the single-sweep method) are combined with ab initio molecular dynamics to study possible local mechanisms for the diffusion of hydrogen in sodium alanates. These compounds may help to understand key properties of solid state hydrogen storage materials. In this work, the identity of a mobile species observed in experiments characterizing the first dissociation reaction of sodium alanates is investigated. The activation barrier of two suggested processes for hydrogen diffusion in Na₃AlH₆ is evaluated and, by comparing our results with available experimental information, we are able to discriminate among them and to show that one is compatible with the observed signal while the other is not.

Original language	English (US)
Pages (from-to)	187-206
Number of pages	20
Journal	Scientific Modeling and Simulation SMNS
Volume	15
Issue number	1-3
DOIs	https://doi.org/10.1007/s10820-008-9097-x
State	Published - 2008

Keywords

Activated processes
Free energy reconstruction
Hydrogen storage
Radial basis reconstruction
Single-sweep method
Sodium Alanates
String method
TAMD

ASJC Scopus subject areas

Computational Mechanics
Modeling and Simulation
General Materials Science
Mechanics of Materials

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10.1007/s10820-008-9097-x

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title = "Calculations of free energy barriers for local mechanisms of hydrogen diffusion in alanates",

abstract = "Brute force histogram calculation and a recently developed method to efficiently reconstruct the free energy profile of complex systems (the single-sweep method) are combined with ab initio molecular dynamics to study possible local mechanisms for the diffusion of hydrogen in sodium alanates. These compounds may help to understand key properties of solid state hydrogen storage materials. In this work, the identity of a mobile species observed in experiments characterizing the first dissociation reaction of sodium alanates is investigated. The activation barrier of two suggested processes for hydrogen diffusion in Na3AlH6 is evaluated and, by comparing our results with available experimental information, we are able to discriminate among them and to show that one is compatible with the observed signal while the other is not.",

keywords = "Activated processes, Free energy reconstruction, Hydrogen storage, Radial basis reconstruction, Single-sweep method, Sodium Alanates, String method, TAMD",

author = "Michele Monteferrante and Sara Bonella and Simone Meloni and Eric Vanden-Eijnden and Giovanni Ciccotti",

note = "Funding Information: Acknowledgements The authors are grateful to R. Cantelli, O. Palumbo and A. Paoloni for pointing out the experimental problem at the basis of this work and for discussions related to the model employed here, and to L. Maragliano for useful discussions about the single-sweep method and TAMD. We also thank R. Vuilleumier for contributing to the definition of the collective variables and of the pseudopotentials, and for suggestions on the most efficient implementation of the TAMD procedure in CPMD. Funding from the Ministero dell{\textquoteright}Ambi-ente e della Tutela del Territorio e del Mare is gratefully acknowledged along with the computational resources provided by CASPUR. E. V-E. acknowledges support from NSF grants DMS02-09959 and DMS02-39625, and ONR grant N00014-04-1-0565. Finally, the authors wish to acknowledge C. Dellago and the inspiring hospitality of the Erwin Schr{\"o}dinger Institut in Vienna during the program “Metastability and rare events in complex systems”.",

year = "2008",

doi = "10.1007/s10820-008-9097-x",

language = "English (US)",

volume = "15",

pages = "187--206",

journal = "Scientific Modeling and Simulation SMNS",

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publisher = "Springer Netherlands",

number = "1-3",

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T1 - Calculations of free energy barriers for local mechanisms of hydrogen diffusion in alanates

AU - Monteferrante, Michele

AU - Bonella, Sara

AU - Meloni, Simone

AU - Vanden-Eijnden, Eric

AU - Ciccotti, Giovanni

N1 - Funding Information: Acknowledgements The authors are grateful to R. Cantelli, O. Palumbo and A. Paoloni for pointing out the experimental problem at the basis of this work and for discussions related to the model employed here, and to L. Maragliano for useful discussions about the single-sweep method and TAMD. We also thank R. Vuilleumier for contributing to the definition of the collective variables and of the pseudopotentials, and for suggestions on the most efficient implementation of the TAMD procedure in CPMD. Funding from the Ministero dell’Ambi-ente e della Tutela del Territorio e del Mare is gratefully acknowledged along with the computational resources provided by CASPUR. E. V-E. acknowledges support from NSF grants DMS02-09959 and DMS02-39625, and ONR grant N00014-04-1-0565. Finally, the authors wish to acknowledge C. Dellago and the inspiring hospitality of the Erwin Schrödinger Institut in Vienna during the program “Metastability and rare events in complex systems”.

PY - 2008

Y1 - 2008

N2 - Brute force histogram calculation and a recently developed method to efficiently reconstruct the free energy profile of complex systems (the single-sweep method) are combined with ab initio molecular dynamics to study possible local mechanisms for the diffusion of hydrogen in sodium alanates. These compounds may help to understand key properties of solid state hydrogen storage materials. In this work, the identity of a mobile species observed in experiments characterizing the first dissociation reaction of sodium alanates is investigated. The activation barrier of two suggested processes for hydrogen diffusion in Na3AlH6 is evaluated and, by comparing our results with available experimental information, we are able to discriminate among them and to show that one is compatible with the observed signal while the other is not.

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Calculations of free energy barriers for local mechanisms of hydrogen diffusion in alanates

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Keywords

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