硅气凝胶电子能谱的测定与量子化学研究

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，建立了聚硅酸钠米粒子簇模型，利用从头算方法，在HF／3－21G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。

Measurements of Electronic Spectra and Researches on Quantum Chemistry for Silica Aerogels

The electron spectrum of silica aerogels is measured by electron spectroscope. The Si 1s ionization energy of silica aerogels is 1.711～1.762 keV. The ionization energies are increased with the particle size of silica aerogels. The size effects on electron spectrum of silica aerogels have been found. According to the poly-silicate nanocluster model and Koopmens’ theory. The geometry of nanocluster is optimized by using ab initio SCF MO method at the level of HF／3-21G. The analyzed gradient of energy was used in the computational process. The molecular orbital level and electron spectrum peek of nanocluster are calculated. The results show that the ionization energy is 1.862～1.875 keV, which are in agreement with the experiment results.