钨酸铅晶体中与铅空位有关的电子结构和色心模型研究

根据密度泛函理论对钨酸铅晶体中铅空位周围的晶格进行了结构优化，计算得到铅空位周围的晶格结构、电子态密度分布和偏振吸收光谱；计算结果表明钨酸铅晶体中铅空位的两价负电性是通过铅空位周围的氧共同抓获两个空穴来维持局部电中性的，即铅空位周围形成的色心模型为［O₂^3--V_Pb^2--O₂^3-］，不同的氧离子抓获空穴方式不同形成不同的色心，对应不同的吸收带；根据吸收带的偏振性质，提出了各个关键词：钨酸铅晶体色心模型电子结构偏振特性

Electronic structures and color centers of PbWO4 with lead vacancy

The electronics structures and absorption spectra of polarized light for the PWO crystal containing Vpb^2- have been calculated using CASTEP code with lattice structure optimization. The optimized lattice structures around lead vacancy in the PWO have been obtained. The color center models and their corresponding absorption spectra have been proposed according to the experimental results of the lattice structures and the electronic structures around the lead vacancy. The negative divalent Vpb^2- should trap two holes to maintain the local neutrality. The possible way of the formation of the hole centers is one trapped hole shared by two O^2- ions nearest to Vpb^2- and other one shared by another two O^2- ions nearest to Vpb^2- forming [ O2^3- - Vpb^2- -O2^3- ]. The different ways of O^2- ions trapping the holes will form different color centers corresponding to different absorption bands. The color center models around Vpb^2- have been proposed.