Theoretical Study on Adsorption of Na+ and Na+(H2O)n (n = 1-6) on a Clean Si(111) Surface
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- 作者：Yongjun Liu ; Zhiguo Wang ; Yourui Suo
- 刊名：Journal of Physical Chemistry C
- 出版年：2007
- 出版时间：March 1, 2007
- 年：2007
- 卷：111
- 期：8
- 页码：3427 - 3432
- 全文大小：270K
- 年卷期：v.111,no.8(March 1, 2007)
- ISSN：1932-7455
文摘
To model the adsorption of Na+ in aqueous solution on the semiconductor surface, the interactions of Na+and Na+(H2O)n (n = 1-6) with a clean Si(111) surface were investigated by using hybrid density functionaltheory (B3LYP) and M
ller-Plesset second-order perturbation (MP2) methods. The Si(111) surface wasdescribed with Si8H12, Si16H20, and Si22H21 cluster models. The effect of the basis set superposition error(BSSE) was taken into account by applying the counterpoise (CP) correction. The calculated results indicatedthat the interactions between the Na+ cation and the dangling bonds of the Si(111) surface are primarilyelectrostatic with partial orbital interactions. The magnitude of the binding energies depends weakly on theadsorption sites and the size of the clusters. When water molecules are present, the interaction between theNa+ and Si(111) surfaces weakens and the binding energy has the tendency to saturate. On a Si22H21 clusterdescribed surface, the optimized Na+-surface distance for Na+(H2O)5 adsorbed at on-top site is 4.16 Å andthe CP-corrected binding energy (MP2) is -35.4 kJ/mol, implying a weakly adsorption of hydrated Na+cation on clean Si(111) surface.
ller-Plesset second-order perturbation (MP2) methods. The Si(111) surface wasdescribed with Si8H12, Si16H20, and Si22H21 cluster models. The effect of the basis set superposition error(BSSE) was taken into account by applying the counterpoise (CP) correction. The calculated results indicatedthat the interactions between the Na+ cation and the dangling bonds of the Si(111) surface are primarilyelectrostatic with partial orbital interactions. The magnitude of the binding energies depends weakly on theadsorption sites and the size of the clusters. When water molecules are present, the interaction between theNa+ and Si(111) surfaces weakens and the binding energy has the tendency to saturate. On a Si22H21 clusterdescribed surface, the optimized Na+-surface distance for Na+(H2O)5 adsorbed at on-top site is 4.16 Å andthe CP-corrected binding energy (MP2) is -35.4 kJ/mol, implying a weakly adsorption of hydrated Na+cation on clean Si(111) surface.