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arXiv · 2110.06757

Absence of proton tunneling during the hydrogen bond symmetrization in $\delta$-AlOOH

Florian Trybel·Thomas Meier·Biao Wang·Gerd Steinle-Neumann
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Abstract

$\delta$-AlOOH is of significant crystallochemical interest due to a subtle structural transition near 10 GPa from a $P2_1nm$ to a $Pnnm$ structure, the nature and origin of hydrogen disorder, the symmetrization of the O-H$\cdots$O hydrogen bond and their interplay. We perform a series of density functional theory based simulations in combination with high-pressure nuclear magnetic resonance experiments on $\delta$-AlOOH up to 40 GPa with the goal to better characterize the hydrogen potential and therefore the nature of hydrogen disorder. Simulations predict a phase transition in agreement with our nuclear magnetic resonance experiments at $10-11$ GPa and hydrogen bond symmetrization at $14.7$ GPa. Calculated hydrogen potentials do not show any double-well character and there is no evidence for proton tunneling in our nuclear magnetic resonance data.

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Florian Trybel, Thomas Meier, Biao Wang, Gerd Steinle-Neumann. 2021-10-13. Absence of proton tunneling during the hydrogen bond symmetrization in $\delta$-AlOOH. https://doi.org/10.1103/physrevb.104.104311

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