含铅氧空位对的PbWO_4晶体光学性质及其偏振特性的模拟计算

Simulation on the optical polarized properties for the PbWO_4 crystal containing a pair of V_(Pb)^(2-)-V_O^(2+)

利用完全势缀加平面波局域密度泛函近似,按照能量最低原理采用共轭梯度方法,对含铅氧空位对的PbWO4晶体进行结构优化处理。在此基础上,计算了含铅氧空位对的PbWO4晶体的电子结构、复数折射率、介电函数及吸收光谱的偏振特性,并与完整的PbWO4晶体进行了比较。结果表明PWO晶体中铅氧空位对的存在不会引起在可见和近紫外区域的吸收。

The electronic structure, dielectric function, complex reflectivity index and absorption spectra on the polarized light in the perfect PbWO4 (PWO) crystal and the PWO crystal containing a pair of VPb2--Vo2+ have been calculated using full-potential (linearized) augmented plane-wave ((L)APW) + local orbitals (lo) method. The calculated results have been discussed in detail. The peaks of the absorption spectra corresponding which electronic transition have been studied. The optical properties of PWO crystal containing a pair of VPb2--Vo2+ occur anisotropy. It may be caused by the anisotropy of PWO crystal lattice structure. The results indicate that the perfect PWO crystal does not occur absorption band in the visible region. By analyzing the calculated results of the PWO cluster containing a pair of VPb2--Vo2+, it predicates that all the 350 nm, 420 nm and 500-700 nm absorption bands can not be ascribed to the existence of the pair of VPb2--Vo2+ in PWO.