Thermal and Electronic Fluctuations of Flexible Adsorbed Molecules: Azobenzene on Ag(111).
Thermal and Electronic Fluctuations of Flexible Adsorbed Molecules: Azobenzene on Ag(111).
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DOI：
10.1103/physrevlett.116.146101
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发表时间：
2016-03
影响因子：
8.6
通讯作者：
R. Maurer;Wei Liu;I. Poltavsky;T. Stecher;H. Oberhofer;K. Reuter;A. Tkatchenko
中科院分区：
文献类型：
--
作者：
R. Maurer;Wei Liu;I. Poltavsky;T. Stecher;H. Oberhofer;K. Reuter;A. Tkatchenko
以偶氮苯在Ag(111)表面上的分子开关C_(12)H_(10)N_2为例，研究了电子和热集体涨落对柔性吸附材料在表面的有限温度吸附性质的影响。利用第一性原理分子动力学模拟，我们得到了准确地解释熵贡献的吸附自由能，而多体色散相互作用的包含则解释了支配吸附物质结合的电子关联。我们发现吸附产物的性质是强熵驱动的，可以用动力学分子脱附预因子10^{24}S^{-1}来判断，这大大超过了以前报道的估计。我们将这种效应与结构和电子可观测到的可观波动联系在一起。我们的计算与程序升温脱附测量的比较表明，有限温度效应在柔性分子与可极化表面的接触中起主导作用，最近发展起来的第一性原理方法为揭示这种复杂系统中的新的集体行为提供了一个最佳工具。
We investigate the thermal and electronic collective fluctuations that contribute to the finite-temperature adsorption properties of flexible adsorbates on surfaces on the example of the molecular switch azobenzene C_{12}H_{10}N_{2} on the Ag(111) surface. Using first-principles molecular dynamics simulations, we obtain the free energy of adsorption that accurately accounts for entropic contributions, whereas the inclusion of many-body dispersion interactions accounts for the electronic correlations that govern the adsorbate binding. We find the adsorbate properties to be strongly entropy driven, as can be judged by a kinetic molecular desorption prefactor of 10^{24} s^{-1} that largely exceeds previously reported estimates. We relate this effect to sizable fluctuations across structural and electronic observables. A comparison of our calculations to temperature-programed desorption measurements demonstrates that finite-temperature effects play a dominant role for flexible molecules in contact with polarizable surfaces, and that recently developed first-principles methods offer an optimal tool to reveal novel collective behavior in such complex systems.