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O: Fachverband Oberflächenphysik
O 53: Poster Session IV: Poster to Mini-Symposium: Frontiers of electronic-structure theory I
O 53.5: Poster
Tuesday, March 2, 2021, 13:30–15:30, P
Tunnelling with Non-Adiabatic Effects: H-Diffusion in Pd — •Eszter Sarolta Pós1, Yair Litman1, and Mariana Rossi1,2 — 1MPI for the Structure and Dynamics of Matter, Hamburg, Germany — 2Fritz Haber Institute of the Max Planck Society, Berlin, Germany
Hydrogen diffusion in metals is a fundamental process in areas like energy storage devices and hydrogen separation membranes. However, the accurate theoretical description of it is challenging because (1) nuclear quantum effects (NQEs) such as nuclear tunnelling play an important role even at room temperature due to the light mass of the hydrogen atom; (2) the excitation and relaxation of electron-hole pairs around the Fermi level give rise to non-adiabatic effects (NAEs) that alter the system dynamics. In this work, we present a novel approach that combines the ring polymer instanton formalism [1] with ab initio electronic friction [2,3], allowing us to include both NQEs and NAEs in the rate-calculation of H-diffusion between interstitial sites of Pd. Our approach has been implemented into the i-PI code [4] including the spatial dependence of the electronic friction tensor which facilitates the study of nuclear tunnelling on metallic systems with unprecedented realistic first-principles simulations.
[1] J. O. Richardson, JCP 144, 114106 (2016). [2] M. Head-Gordon, J. C. Tully, JCP 96, 3939 (1992). [3] R. J. Maurer, M. Askerka, V. S. Batista, J. C. Tully, PRB 94, 115432 (2016). [4] V. Kapil, et al., CPC 236, 214 (2019).