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Acta Physico-Chimica Sinica  2006, Vol. 22 Issue (04): 445-450    DOI: 10.3866/PKU.WHXB20060411
Article     
A Density-functional Theory Study of Hydrogen Adsorption on Ti(0001) Surface
CHEN Wen-Bin;TAO Xiang-Ming;ZHAO Xin-Xin;TAN Ming-Qiu
Department of Physics, Zhejiang University, Hangzhou 310027, P. R. China
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Abstract  The influence of hydrogen contamination on the atomic geometry of Ti(0001) surface have been studied by using the density-functional theory and the projector-augmented wave(PAW) method. Based on the optimized structural parameters of hcp Ti from the PAW total energy calculation, the surface relaxation, surface energy, and work function of clean Ti(0001) surface were calculated in the same way. The adsorption geometries and total energies of several coverages of hydrogen on Ti(0001) surface including p(1×1),p(1×2),3^1/2×3^1/2R30[deg], and p(2×2), were studied for the hcp and fcc site absorptions combined with the both sites occupation in p(1×1) structure. These results suggest that the Ti(0001) p(1×1)/H geometry has the largest energy gain among the above conformations, so under the condition of low coverage and low H2 pressure, the most possible conformation is p(1×1)-H adsorption. The shrink of Ti(0001) surface with H contamination was -3.7% from available experiments and this work yields -2.85% for hcp and -4.31% for fcc adsorption geometries, respectively. It is deduced that the most possible adsorption configuration for a hydrogen contaminated Ti(0001) surface is a mixture of hcp and fcc adsorptions. For a clean Ti(0001) surface the surface contraction is calculated to be near -7.0% while the experimental measurement predicted -4.9%. This observation implies that even for a “clean” Ti(0001) surface there is still about 13.6% surface area covered with hydrogen adsorption. These results reflect that the hydrogen contamination could affect the Ti(0001) surface structure dramatically. Furthermore the present study could yield a conclusion naturally that the shrink of the Ti(0001) surface will be reduced with the increase of H atom adsorption below 1.0 ML(monolayer).

Received: 21 September 2005      Published: 10 April 2006
Corresponding Authors: TAO, Xiang-Ming     E-mail: mqtan@zju.edu.cn
Cite this article:

CHEN Wen-Bin;TAO Xiang-Ming;ZHAO Xin-Xin;TAN Ming-Qiu. A Density-functional Theory Study of Hydrogen Adsorption on Ti(0001) Surface. Acta Physico-Chimica Sinica, 2006, 22(04): 445-450.

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http://www.whxb.pku.edu.cn/Jwk_wk/wlhx/10.3866/PKU.WHXB20060411     OR     http://www.whxb.pku.edu.cn/Jwk_wk/wlhx/Y2006/V22/I04/445

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