一维二氧化硅纳米材料是当前发光材料的研究热点之一,作为高效发光材料的候选材料,需要了解其电子结构参数和光谱数据。选取一维链式结构的(SiO₂)₁₀分子为研究对象,在利用密度泛函B3LYP方法得到分子基态构型的基础上,研究外加电场强度对该分子电子结构特性的影响;采用TD-B3LYP方法系统分析了外加电场强度对分子激发特性的影响规律。结果表明:无外加电场时,得到的分子电子结构参数与已有文献值完全吻合;各单元环中Si-O键键长增加或减小与施加电场的方向密切相关;在激发特性方面,分子在240 nm附近出现的吸收峰与已有实验结果相吻合,而得到的强度更强的180 nm吸收峰是少有文献提及的;随外加电场强度增强,各激发态激发能减小,吸收谱线波长出现一定的红移;特定的外加电场会使一些禁戒的激发态变为可跃迁的激发态,这意味着可以利用特定的外加电场调控来实现分子吸收某些特殊波长的谱线。

One-dimensional silicon dioxide nanomaterials are one of the hot topics in the research of luminescent materials. As a candidate material for high-efficiency luminescent materials, it is necessary to understand its electronic structure parameters and spectral data. One-dimensional (SiO2)10 molecule with chain structure is selected as the research object, and the molecular ground state is obtained by the density functional B3LYP method. The effect of external electric field intensity on the electronic structure characteristics of the molecule is investigated systematically. Meanwhile, the excitation characteristics of the molecule at different electric field intensities are explored using the time-dependent density functional theory TD-B3LYP. The results show that the obtained molecular electronic structure parameters agree well with the existing literature values. The increase or decrease of the Si-O bond length in each unit ring is entirely determined by the direction of applied electric field. For the excitation characteristics, the absorption peak appearing around 240 nm, which is consistent with the existing experimental results, and the obtained 180 nm absorption peak with relatively high intensity is rarely mentioned in the literature. With the increase of the external electric field intensity, the excitation energy of the excited states decreases, and the wavelength of the absorption spectra has a red shift. At the same time, it has been found that certain external electric fields can make some forbidden excited states into transitional excited states, which means that a specific external electric field regulation can be used for the molecule to absorb the spectrum at some certain wavelengths.