Saalfrank Peter, Juaristi J I, Alducin M, Blanco-Rey M, Muiño R Díez
Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam, Germany.
Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain.
J Chem Phys. 2014 Dec 21;141(23):234702. doi: 10.1063/1.4903309.
Using density functional theory and Ab Initio Molecular Dynamics with Electronic Friction (AIMDEF), we study the adsorption and dissipative vibrational dynamics of hydrogen atoms chemisorbed on free-standing lead films of increasing thickness. Lead films are known for their oscillatory behaviour of certain properties with increasing thickness, e.g., energy and electron spillout change in discontinuous manner, due to quantum size effects [G. Materzanini, P. Saalfrank, and P. J. D. Lindan, Phys. Rev. B 63, 235405 (2001)]. Here, we demonstrate that oscillatory features arise also for hydrogen when chemisorbed on lead films. Besides stationary properties of the adsorbate, we concentrate on finite vibrational lifetimes of H-surface vibrations. As shown by AIMDEF, the damping via vibration-electron hole pair coupling dominates clearly over the vibration-phonon channel, in particular for high-frequency modes. Vibrational relaxation times are a characteristic function of layer thickness due to the oscillating behaviour of the embedding surface electronic density. Implications derived from AIMDEF for frictional many-atom dynamics, and physisorbed species will also be given.
利用密度泛函理论和含电子摩擦的从头算分子动力学（AIMDEF），我们研究了化学吸附在厚度不断增加的独立铅膜上的氢原子的吸附和耗散振动动力学。铅膜因其某些性质随厚度增加而呈现振荡行为而闻名，例如，由于量子尺寸效应，能量和电子溢出以不连续的方式变化[G. Materzanini, P. Saalfrank, and P. J. D. Lindan, Phys. Rev. B 63, 235405 (2001)]。在此，我们证明当氢化学吸附在铅膜上时也会出现振荡特征。除了吸附质的静态性质外，我们专注于H-表面振动的有限振动寿命。如AIMDEF所示，通过振动-电子空穴对耦合的阻尼明显超过振动-声子通道，特别是对于高频模式。由于嵌入表面电子密度的振荡行为（特性），振动弛豫时间是层厚度的特征函数。还将给出AIMDEF对摩擦多原子动力学和物理吸附物种的影响。
