用胶体-原子薄片模型计算W(100)-Cs吸附系统的逸出功
THE WORK FUNCTION CALCULATIONS FOR W(100)-Cs ADSORBED SYSTEMS BYJELLIUM ON ATOMIC SLAB MODEL
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摘要: 碱或碱土金属的原子吸附于过渡金属表面时,会使后者的逸出功急剧下降。作者提出了胶体-原子薄片模型来研究这一现象。过渡金属基底用薄膜线性级加平面波(LAPW)法精确处理,而简单金属覆层则用胶体(jellium)模拟。此模型可在充分考虑构成基底的过渡金属特点的情况下,研究单原子层覆盖度以下的吸附系统的电子性质。 文中给出了计算所得W(100)面吸附Cs后的-曲线。所得逸出功极小值min=1.441.48eV与实验结果(min=1.351.55eV)吻合较好,文中还讨论了Ev参量的选择等问题。
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Abstract: The work functions of transition metals vary drastically wirh the coverage of adsorbed alkali or alkaline earth metal atoms. This phenomenon is studied theoretically by a refined model, i.e., the transition-metal substrate is treated whh high accuracy by the film LAPW method, while the simple metal overlayer is simulated by the jellium model. Computation of the electronic structure of the adsorbed system with a coverage of lower than monolayer will become possible by using this model. The variations of work function () with the converage () of Cs on the W-substrate are presemted. the calculated min=1.441.48eV is in goood agreement with the experimental value (1.351.55eV). The close dependance of the results on the choice of parameter, Ev, is also discussed. -
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