Department of Chemistry, University of Massachusetts , Amherst, Massachusetts 01003, United States.
J Phys Chem A. 2013 Sep 12;117(36):8651-9. doi: 10.1021/jp402987w. Epub 2013 May 9.
The dissociative chemisorption of methane on Pt(110)-(1×2) is examined, with a focus on how the reaction dynamics are modified by the motion of the lattice atoms. The barriers to dissociation are found to be lowest at the step edges. The relaxation of the lattice in the presence of the dissociating molecule is found to be far more complicated than on the smooth surfaces of Pt and Ni. The dissociative sticking probabilities are computed using a full-dimensional treatment based on the reaction path Hamiltonian that includes all 15 molecular degrees of freedom and the effects of lattice motion. The potential energy surface and all parameters in our model are computed from first principles. The effects of lattice motion are strong, but not significantly larger than for dissociation on smoother surfaces. Vibrational excitation of the molecule can significantly enhance reactivity, though this effect varies from mode to mode. Agreement with recent experiments with regard to the variation of reactivity with translational energy and substrate temperature is good.
研究了甲烷在 Pt(110)-(1×2)上的离解化学吸附，重点关注晶格原子运动如何改变反应动力学。发现解离的势垒在台阶边缘处最低。在离解分子存在的情况下，晶格弛豫比 Pt 和 Ni 的光滑表面复杂得多。使用基于反应路径哈密顿量的全维处理方法计算离解 sticking 概率，该方法包括所有 15 个分子自由度和晶格运动的影响。我们模型中的势能面和所有参数都是从第一性原理计算得到的。晶格运动的影响很强，但并不比在更光滑的表面上的解离大很多。分子的振动激发可以显著提高反应活性，尽管这种效应因模式而异。与最近关于反应活性随平动能量和衬底温度变化的实验结果吻合良好。
