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为了研究钨酸铅晶体中铅空位对光学性质的影响,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,对含铅空位的PbWO4 (PWO)晶体进行结构优化处理。计算了含铅空位的PWO晶体的电子结构、复数折射率、介电函数及吸收光谱,并与完整的PWO晶体进行了比较。结果表明:完整的PWO晶体在可见和近紫外区域内无吸收,而含铅空位的PWO晶体在可见和近紫外区域出现2个明显的吸收峰,这2 个吸收峰可分解成4个高斯线型的吸收带,它们的峰值分别为350 nm、405 nm、550 nm和670 nm。可以得出这样的推论:PWO晶体中350 nm、420 nm、550 nm和670 nm 吸收带的出现都与铅空位的存在有关。
In order to study the influence of Pb vacancy on the optical properties of lead tungstate crystals, the PbWO4 (PWO) crystal containing lead vacancies was constructed by the method of conjugate gradient according to the lowest energy principle using the full potential solution plus surface wave density functional approximation. Optimization. The electronic structure, complex refractive index, dielectric function and absorption spectrum of PWO crystal with lead vacancy were calculated and compared with the intact PWO crystal. The results show that intact PWO crystals have no absorption in the visible and near-ultraviolet region, whereas PWO crystals with lead-containing vacancies have two obvious absorption peaks in the visible and near ultraviolet region, which can be decomposed into four Gaussian lines Type absorption bands with peak values of 350 nm, 405 nm, 550 nm and 670 nm, respectively. It can be deduced that the presence of absorption bands at 350 nm, 420 nm, 550 nm and 670 nm in PWO crystals is related to the presence of lead vacancies.