Experimental and theoretical study of multi-quantum vibrational excitation: NO(v = 0→1,2,3) in collisions with Au(111).
Experimental and theoretical study of multi-quantum vibrational excitation: NO(v = 0→1,2,3) in collisions with Au(111).
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DOI：
10.1021/jp400313b
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发表时间：
2013-08
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影响因子：
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通讯作者：
K. Golibrzuch;A. Kandratsenka;I. Rahinov;R. Cooper;D. Auerbach;A. Wodtke;C. Bartels
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文献类型：
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作者：
K. Golibrzuch;A. Kandratsenka;I. Rahinov;R. Cooper;D. Auerbach;A. Wodtke;C. Bartels
我们测量了NO（v = 0）分子与Au（111）表面碰撞时振动激发的绝对几率，入射平移能量为0.4 eV，表面温度为300 ~ 1100 K。除了先前报道的激发到v = 1和v = 2，我们观察到激发到v = 3。激发概率表现出Arrhenius依赖于表面温度，表明占主导地位的激发机制是非绝热耦合的电子空穴对。实验数据进行了分析，在最近推出的动力学模型，其中扩展到包括四个振动状态。我们描述了一个子群分解的动力学模型，这使我们能够检查振动人口转移途径。分析表明，单独的顺序途径（v = 0 → 1 → 2和v = 0 → 1 → 2 → 3）不能充分描述v = 2或3的产生。此外，我们进行了第一性原理分子动力学计算，通过一个独立的电子表面跳跃（IESH）算法，这需要作为输入的从头算势能超曲面（PES）和非绝热耦合矩阵元素，都从密度泛函理论（DFT）获得的电子非绝热动力学。虽然基于IESH的模拟很好地再现了v = 1的数据，但它们略微低估了v = 2的激发概率，并且显著低估了v = 3的激发概率。此外，IESH的实施似乎高估了连续能量转移途径的重要性。我们提出了一些建议，以改善这种IESH为基础的模型。
We measured absolute probabilities for vibrational excitation of NO(v = 0) molecules in collisions with a Au(111) surface at an incidence energy of translation of 0.4 eV and surface temperatures between 300 and 1100 K. In addition to previously reported excitation to v = 1 and v = 2, we observed excitation to v = 3. The excitation probabilities exhibit an Arrhenius dependence on surface temperature, indicating that the dominant excitation mechanism is nonadiabatic coupling to electron-hole pairs. The experimental data are analyzed in terms of a recently introduced kinetic model, which was extended to include four vibrational states. We describe a subpopulation decomposition of the kinetic model, which allows us to examine vibrational population transfer pathways. The analysis indicates that sequential pathways (v = 0 → 1 → 2 and v = 0 → 1 → 2 → 3) alone cannot adequately describe production of v = 2 or 3. In addition, we performed first-principles molecular dynamics calculations that incorporate electronically nonadiabatic dynamics via an independent electron surface hopping (IESH) algorithm, which requires as input an ab initio potential energy hypersurface (PES) and nonadiabatic coupling matrix elements, both obtained from density functional theory (DFT). While the IESH-based simulations reproduce the v = 1 data well, they slightly underestimate the excitation probabilities for v = 2, and they significantly underestimate those for v = 3. Furthermore, this implementation of IESH appears to overestimate the importance of sequential energy transfer pathways. We make several suggestions concerning ways to improve this IESH-based model.