Centro de Física de Materiales (CSIC-UPV/EHU)-Materials Physics Center MPC, San Sebastián, Spain.
Phys Chem Chem Phys. 2012 May 28;14(20):7471-80. doi: 10.1039/c2cp40229g. Epub 2012 Apr 24.
We study the adsorption dynamics of N(2) on the Fe(110) surface. Classical molecular dynamics calculations are performed on top of a six-dimensional potential energy surface calculated within density functional theory. Our results show that N(2) dissociation on this surface is a highly activated process that takes place along a very narrow reaction path with an energy barrier of around 1.1 eV, which explains the measured low reactivity of this system. By incorporating energy exchange with the lattice in the dynamics, we also study the non-dissociative molecular adsorption process. From the analysis of the potential energy surface, we observe the presence of two distinct N(2) adsorption wells. Our dynamics calculations show that the relative population of these adsorption sites varies with the incident energy of the molecule and the surface temperature. We find an activation energy of around 150 meV that prevents molecular adsorption under thermal and hypothermal N(2) gas exposure of the surface. This finding is also consistent with the available experimental information.
我们研究了 N(2) 在 Fe(110)表面上的吸附动力学。在密度泛函理论计算的六维势能表面上进行了经典分子动力学计算。我们的结果表明，N(2)在该表面上的离解是一个高度激活的过程，沿着一条非常狭窄的反应路径进行，能量势垒约为 1.1 eV，这解释了该系统测量到的低反应性。通过在动力学中纳入与晶格的能量交换，我们还研究了非离解分子吸附过程。从势能表面的分析中，我们观察到存在两个不同的 N(2)吸附阱。我们的动力学计算表明，这些吸附位的相对分布随分子的入射能量和表面温度而变化。我们发现，在表面受到热和亚热 N(2)气体暴露时，大约 150 meV 的活化能阻止了分子的吸附。这一发现也与现有的实验信息一致。
