Related Experiment Video
Updated: May 17, 2026

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis
Published on: March 29, 2016
The quantum free energy barrier for hydrogen vacancy diffusion in Na3AlH6
Adolfo Poma1, Michele Monteferrante, Sara Bonella
1Dipartimento di Fisica Università La Sapienza, P.le A. Moro 5, 00185 Roma, Italy.
Abstract:
The path integral single sweep method is used to assess quantum effects on the free energy barrier for hydrogen vacancy diffusion in a defective Na(3)AlH(6) crystal. This process has been investigated via experiments and simulations due to its potential relevance in the H release mechanism in sodium alanates, prototypical materials for solid state hydrogen storage. Previous computational studies, which used density functional methods for the electronic structure, were restricted to a classical treatment of the nuclear degrees of freedom. We show that, although they do not change the qualitative picture of the process, nuclear quantum effects reduce the free energy barrier height by about 18% with respect to the classical calculation improving agreement with available neutron scattering data.
Related Concept Videos
Free Energy Changes for Nonstandard States
Imperfections in Crystal Structure: Stoichiometric Point Defects
Fermi Level Dynamics
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
Atomic Nuclei: Nuclear Spin State Population Distribution
The Pauli Exclusion Principle
Nuclear Binding Energy

