中文摘要：

利用光学气敏材料吸附气体来检测气体成分及浓度,成为了大家的一个研究热点.采用基于密度泛函理论（DFT-D）体系下的第一性原理平面波超软赝势方法,研究了含氧空位金红石相TiO2（110）表面,SnO2（110）表面和GeO2（110）表面吸附HCl气体后,表面结构的氧化性能、态密度、电荷分布、差分电荷密度以及光学性质,讨论吸附对光学气敏传感特性的影响.研究发现：HCl气体均易吸附于含氧空位金红石相TiO2,SnO2和GeO2表面;且吸附后的稳定性为：TiO2〉SnO2〉GeO2;氧化性是影响吸附能力和光学气敏传感性能的重要因素,HCl分子吸附于表面后其氧化性强弱为：TiO2氧空位〉SnO2氧空位〉GeO2氧空位;从态密度和光学性质分析发现,含氧空位金红石相TiO2（110）吸附HCl分子后,光学性质的改变最为明显,特别是对于500-700 nm的光,TiO2具有很好的光学气敏传感效应,可作为一种较为理想的光学气敏传感材料.

英文摘要：

Recently, optical gas sensing materials become a research hotspot, which can detect the concentration of environment gas sensitively and quickly. Environment gas molecule adsorbed on gas sensing materials surface will cause changes in the optical properties of materials, so as to achieve the parameters of gas composition and concentration. Rutile phase TiO2, SnO2 and GeO2 are widely used in optical gas sensing semiconductor materials. The three semiconductor have the same structure type, and the （110） surface has the lowest energy. The band gap of the three are 3.0, 3.6, 5.04 eV, and their photo-chemical properties have been used in many fields. Hydrogen chloride is a dangerous gas, which has a very strong odor, colorless, non-flammable, easily soluble in water and strong corrosive. So detection the concentration of HC1 gas in environment is very important. In this paper, the microscopic mechanism of HC1 gas adsorption on TiO2, SnO2 and GeO2（110） surface is studied, which adopted first-principles plane-wave ultrasoft pseudo-potential method based on density functional theory （DFT-D）. The calculation used the castep module in Material Studio software. The DFT-D method deal with electron-related energy of HC1 gas, TiO2, SnO2 and GeO2 surface by Perdew-Burke-Ernzerh （PBE） exchange correlation functional under generalized gradient approximation （GGA） respectively. After HC1 molecule adsorbed on three kinds oxide surface, micro-change and optical gas sensing properties of the three surface were researched including adsorption energy, adsorption distance, density of states, charge population distribution, differential charge density, dielectric function, absorption coefficient and reflectivity, et al. The results showed that： after HC1 gas adsorbed on futile TiO2, SnO2 and GeO2（ll0） surface, the distance of molecule and surface is reduced respect to the initial distance, and the order of distance is： d（TiO2）〈d（Sno2）〈d（GeO2）. The corresponding adsorption energy order is： E?