用膠體-原子薄片模型計算W(100)-Cs吸附系統(tǒng)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: 堿或堿土金屬的原子吸附于過渡金屬表面時,會使后者的逸出功急劇下降。作者提出了膠體-原子薄片模型來研究這一現(xiàn)象。過渡金屬基底用薄膜線性級加平面波(LAPW)法精確處理,而簡單金屬覆層則用膠體(jellium)模擬。此模型可在充分考慮構(gòu)成基底的過渡金屬特點的情況下,研究單原子層覆蓋度以下的吸附系統(tǒng)的電子性質(zhì)。 文中給出了計算所得W(100)面吸附Cs后的-曲線。所得逸出功極小值min=1.441.48eV與實驗結(jié)果(min=1.351.55eV)吻合較好,文中還討論了Ev參量的選擇等問題。
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關(guān)鍵詞:
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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