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利用能谱仪得到了硅气凝胶的K壳层电子能谱 ,测定的硅气凝胶Si在 1s的电子电离能为1.711～ 1.762keV ,并随颗粒尺寸的增大而升高 ,因而确认硅气凝胶的电子能谱也具有尺寸效应 .依据量子化学原理 ,建立了聚硅酸纳米粒子簇模型 .利用从头算方法 ,在HF/3- 2 1G的水平上 ,用解析梯度技术全优化得到了纳米粒子簇的几何构型 .根据Koopmans定理 ,计算了纳米粒子簇的分子轨道能级 ,得到了电子能谱峰的位置 ,理论计算Si在 1s的电子电离能为 1.862～ 1.875keV ,其尺寸效应与实验结果的变化趋势一致 .
The K-shell electron spectra of silica aerogels were obtained by energy dispersive spectroscopy. The measured ionization energies of silicon aerogels Si at 1 s ranged from 1.711 to 1.762keV and were confirmed to increase with increasing particle size The electron spectrum of silicon aerogels also has the size effect.According to the quantum chemistry principle, a polysilicate nanoparticle cluster model was established.Using the ab initio method, the analytical optimization was performed on the level of HF / 3- 2 1G According to the Koopmans theorem, the molecular orbital energy levels of the nanoparticle clusters were calculated, and the position of the electron spectrum peak was obtained. The theoretical ionization energy of Si at 1s was 1.862 ~ 1.875 keV The size effect is consistent with the experimental results.