Modeling surface vibrations and their role in molecular adsorption: a generalized Langevin approach
The atomic vibrations of a solid surface can play a significant role in the reactions of surface-bound molecules, as well as their adsorption and desorption. Relevant phonon modes can involve the collective motion of atoms over a wide array of length scales. In this manuscript, we demonstrate how th...
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Main Authors | , , , |
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Format | Journal Article |
Language | English |
Published |
12.01.2023
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Subjects | |
Online Access | Get full text |
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Summary: | The atomic vibrations of a solid surface can play a significant role in the
reactions of surface-bound molecules, as well as their adsorption and
desorption. Relevant phonon modes can involve the collective motion of atoms
over a wide array of length scales. In this manuscript, we demonstrate how the
generalized Langevin equation can be utilized to describe these collective
motions weighted by their coupling to individual sites. Our approach builds
upon the generalized Langevin oscillator (GLO) model originally developed by
Tully \textit{et al.} We extend the GLO by deriving parameters from atomistic
simulation data. We apply this approach to study the memory kernel of a model
platinum surface and demonstrate that the memory kernel has a bimodal form due
to coupling to both low-energy acoustic modes and high-energy modes near the
Debye frequency. The same bimodal form was observed across a wide variety of
solids of different elemental compositions, surface structures, and solvation
states. By studying how these dominant modes depend on simulation size, we
argue that the acoustic modes are frozen in the limit of macroscopic lattices.
By simulating periodically replicated slabs of various sizes we quantify the
influence of phonon confinement effects in the memory kernel and their
concomitant effect on simulated sticking coefficients. |
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DOI: | 10.48550/arxiv.2301.04873 |