Core level photoemission line shape selection: Atomic adsorbates on iron
Core level photoemission line shape selection: Atomic adsorbates on iron
复制标题
DOI：
10.1002/sia.6770
复制
发表时间：
2020-03
影响因子：
1.7
通讯作者：
M. Acres;H. Hussain;M. Walczak;M. Nikiel;Christopher Sewell;Carles Ràfols i Bellés;E. A. Ahmad;A. S. Walton;C. Muryn;N. Harrison;R. Lindsay
中科院分区：
文献类型：
--
作者：
M. Acres;H. Hussain;M. Walczak;M. Nikiel;Christopher Sewell;Carles Ràfols i Bellés;E. A. Ahmad;A. S. Walton;C. Muryn;N. Harrison;R. Lindsay
芯能级光电子能谱的稳健拟合通常是可靠解释X射线光电子能谱（XPS）数据的核心。一个关键要素是为每个光谱分量采用正确的线形函数。在这项研究中，我们考虑这一主题，侧重于XPS数据的原子吸附物，即O和S，在Fe（110）。探讨了利用密度泛函理论（DFT）生成吸附质投影电子态密度（PDOS）来支持线型选择的可能性。O 1 s核心水平XPS光谱，从各种有序的化学吸附O的覆盖层，都显示出等效的不对称线形。以前的工作表明，这种不对称性是费米能级附近的有限O PDO的结果，允许O 1 s光激发通过电子空穴对激发诱导加权连续的终态。这一起源得到了优化的五层Fe（110）（2 × 2）-O板生成的O DFT-PDOS的证实。还计算了Fe（110）2112-S的吸附物DFT-PDOS。由于与吸附态O相似，费米能级附近的态分布也是连续的，因此，S2 p XPS芯能级也应该具有非对称分布.从Fe（110）2112-S获得的S 2 p XPS数据及其随后的拟合验证了这一预测，表明DFT-PDOS可以帮助线形状选择。
Robust fitting of core level photoemission spectra is often central to reliable interpretation of X‐ray photoelectron spectroscopy (XPS) data. One key element is employment of the correct line shape function for each spectral component. In this study, we consider this topic, focusing on XPS data from atomic adsorbates, namely, O and S, on Fe(110). The potential of employing density functional theory (DFT) for generating adsorbate projected electronic density of states (PDOS) to support line shape selection is explored. O 1s core level XPS spectra, acquired from various ordered overlayers of chemisorbed O, all display an equivalent asymmetric line shape. Previous work suggests that this asymmetry is a result of finite O PDOS in the vicinity of the Fermi level, allowing O 1s photoexcitation to induce a weighted continuum of final states through electron‐hole pair excitation. This origin is corroborated by O DFT‐PDOS generated for an optimised five‐layer Fe(110)(2 × 2)‐O slab. Adsorbate DFT‐PDOS were also computed for Fe(110) 2112 ‐S. As, similar to adsorbed O, there is a significant continuous distribution of states about the Fermi level, it is proposed that the S 2p XPS core levels should also have asymmetric profiles. S 2p XPS data acquired from Fe(110) 2112 ‐S, and their subsequent fitting, verify this prediction, suggesting that DFT‐PDOS could aid line shape selection.