PbWO4晶体F心及F+心吸收带的能级计算

采用离散变分法计算了PbWO4晶体的能带结构，并用F心及F^ 心的类氢离子1S波函数结合离散变分法计算了F心及F^ 心的电子基态能级，计算结果表明，F心及F^ 心电子基态能级分布在禁带中，分别位于距导带底1.97eV(630nm)及2.36eV(525nm)处，它们的吸收跃迁对应于基态到导带底的跃迁，使晶体呈现F心及F^ 心吸收带，化学计量PbWO4晶体的辐照诱导吸收谱位于500-700nm，呈现一个宽吸收带，高斯分解的结果表明；该吸收带是由两个峰值分别位于550nm和680nm的吸收带叠加而成的，这两个吸收带分别对应于F^ 心及F心吸收带，计算结果与实验数据吻合较好。

Calculation on the energy bands of the F and F+centers in PbWO4 crystals

The energy bands of PbWO4 crystal are studied by using discrete variational Xa method. The ground states of both F center and F+ center in stoichiometry PbWO4 crystal are calculated by using the 1S state eigen function of the H-like atom as the trial function. The results show that the ground states of both F center and F+ center fall into the forbidden band of the crystal and situate apart from the bottom of the conduction band 1.97 eV(630 nm) and 2.36 eV(525 nm) respectively. Being excited, the electron of the F center and F+ center can transfer from their ground to the bottom of conduction band forming the F center and F+ center absorption bands respectively. The light irradiation induced absorption spectra of the stoichiometry PbWO4 crystal poccesses a broad band posited between 500~700 nm, which can be decomposed into two Gaussian bands peaking at 550 nm and 680nm respectively. The theoretical results coincide well with the experimental results.