Chemisorption-induced 4f-core-electron binding-energy shifts for surface atoms of W(111), W(100), and Ta(111)
Chemisorption-induced 4f-core-electron binding-energy shifts for surface atoms of W(111), W(100), and Ta(111)
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W(111)、W(100) 和 Ta(111) 表面原子的化学吸附诱导的 4f 核电子结合能变化
DOI：
10.1103/physrevb.25.7388
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发表时间：
1982
影响因子：
3.7
通讯作者：
D. Eastman
中科院分区：
文献类型：
--
作者：
J. V. D. Veen;F. Himpsel;D. Eastman
通过高分辨率同步辐射激发光电子能谱，在Ta和W衬底4f芯能级上解析了氢和氧诱导的化学位移。表面能级通常以100至200 meV连续移动到更高的结合能以增加氢覆盖。这是由于价带中的表面态的淬灭和从衬底到氢原子的电荷转移。吸附氧后，新的核心峰出现在0.4至1.3 eV高的结合能相对于体能级，表明形成强的化学吸附键。元素Z的基底化学位移与稀（Z + 1）x Z 1− x合金中（Z + 1）组分表面偏析热的化学吸附诱导变化相关。
Hydrogen-and oxygen-induced chemical shifts have been resolved in Ta and W substrate 4 f core levels by high-resolution synchrotron-radiation-excited photoemission spectroscopy. The surface levels shift continuously by typically 100 to 200 meV to higher binding energy for increasing hydrogen coverage. This is due to a quenching of surface states in the valence band and a charge transfer from the substrate to the hydrogen atoms. Upon adsorption of oxygen, new core peaks appear at 0.4 to 1.3 eV higher binding energy with respect to the bulk level, indicating the formation of strong chemisorption bonds. Substrate chemical shifts for element Z correlate with chemisorption-induced changes in the heat of surface segregation of the (Z+ 1) constituent in a dilute (Z+ 1) x Z 1− x alloy.