Diffusion dynamics of adsorbates from tunnelling and other quantum effects

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• Roberto Marquardt, Laboratory of Quantum Chemistry, University of Strasbourg, France
• Thursday 18 February 2016, 16:00-17:00
• Mott Seminar Room, Cavendish Laboratory.

If you have a question about this talk, please contact Stephen Walley.

The formula proposed by van Hove in 1954 [1] for the dynamical structure factor (DSF) related to particle scattering at mobile adsorbates has recently been extended to the case when the adsorbates’ excited states have finite lifetimes due to relaxation phenomena [2].

The new formula is evaluated quantum mechanically using wavefunctions, energies and lifetimes of vibrational states obtained for H/Pd(111) from first principle calculations. The results are capable of capturing qualitative features of diffusion rates measured for similar systems [3], if one assumes that the total rate obtained from the DSF is the sum of a diffusion and a friction rate.

In this talk, I present the new formula and show how applications perform on similar systems. In particular I show that quantum effects such as tunnelling and resonances might be important for the diffusion of adsorbates even at room temperature.

References

[1] L. van Hove, Phys. Rev. 95, 249{262 (1954).

[2] T. Firmino, R. Marquardt, F. Gatti, W. Dong, J. Phys. Chem. Lett. 5 4270-4274 (2014).

[3] A. P. Jardine, G. Alexandrowicz, H. Hedgeland, W. Allison, J. Ellis, Phys. Chem. Chem. Phys. 11 3355-3374 (2009).

This talk is part of the Physics and Chemistry of Solids Group series.

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