水在β-氮化硅(0001)面吸附的密度泛函理论研究  

Study of H_2O Adsorption on β-Si_3N_4(0001) by Density Functional Theory

作　　者：王玲[1] 王学业[1] 王寒露[1] 王衡亮[1] 刘爱虹[1] 谭援强[2] 

机构地区：[1]湘潭大学化学学院,湖南湘潭411105 [2]湘潭大学机械工程学院,湖南湘潭411105

出　　处：《摩擦学学报》2007年第1期60-63,共4页Tribology

基　　金：国家自然科学基金资助项目(50675185);湖南省杰出青年基金资助项目(04JJ1010);湖南省教育厅重点项目资助(05A002)

摘　　要：采用密度泛函理论（DTF）的B3LYP方法对H2O在β-Si3N4（0001）面上的吸附进行研究，采用原子簇模拟β-Si3N4（0001）表面，在6-31G^＋水平上计算常温常压下H2O分子在β-Si3N4（0001）表面的吸附构型和吸附能及电荷变化，同时考察温度，压强及预吸附BH3对吸附体系的影响，结果表明：H2O分子通过H原子吸附在β-Si3N4（0001）面的N原子顶位时最有利；当温度为100℃，压强分别为3×10^5-10×10^5Pa时，吸附能为189.59kJ/mol，与常温常压体系相比，吸附能增加了57.19kJ/mol，吸附后O-H键拉长，可能发生解离；在BH3修饰的β-Si3N4（0001）表面上，由于预吸附导致吸附能减少。Density functional theory （DFT） B3LYP method is used to theoretically investigate the interaction of water with β-silicon nitride surface （0001）. The optimization of geometry, the calculation of the adsorption energy and the change of net charge have been performed at 6-31G^＋＊ basis set level using cluster at normal temperature and pressure. The influence of temperature, pressure and BHs modification on the adsorption model has also been studied. The results indicate that the most stable structure is that H2O is adsorbed through H atom of H2O locating on the top of N atom of β-Si3N4（0001 ）. It is found that when the temperature is 100 ℃ and the pressure is 3 ×10^5 - 10 × 10^5 Pa, the adsorption energy is 189.59 kJ/mol, which is increased 57.19 kJ/mol compared with the adsorption model at normal. The elongate of O-H bond probably leads to the decomposition of H2O molecule. After the β- silicon nitride surface （0001） is modified by BHs, the pre-adsorption decreases the adsorption energy of water.

关 键 词：H2O Β-SI3N4 吸附 表面 密度泛函理论(DFT) 

分 类 号：O641[理学—物理化学] TH117.3[理学—化学]