钼酸铅晶体势参数的拟合及本征缺陷的模拟计算

在已有PbWO4晶体势参数的基础上，根据势参数的可转移性，用GULP软件拟合出PbMoO4（PMO）晶体的势参数．利用这些参数计算了PMO的晶格生成能、本征缺陷生成能和缺陷簇的结合能．计算结果表明，Vo^2＋-VPb^2-空位对和F心是PMO晶体中的本征缺陷，并以[Vo^2＋-VPb^2-]空位对和[Vo^2＋ ＋2e]的形式实现电荷补偿．     

Computational Studies in the AlPO4-34 System

The lattice energies of the as-synthesized fluoride-containing chabazite-like aluminophosphate (AlPO₄-34F) and of the corresponding metal-substituted materials [MeAPO-34F, Me = Mn(II), Co(II), Ni(II)] have been calculated in order to investigate the Al-site preference the transition metal substitution in the AlPO₄-34F. The calculations show that the transition metal ions in MeAPO-34F should preferentially occupy octahedral Al³⁺ sites, and kinetic reasons are suggested as an explanation for the actual preference of tetrahedral sites. The lattice energies have also been calculated for the calcined AlPO₄-34F material (AlPO₄-34) and the rehydrated-calcined product (AlPO₄-34h). The AlPO₄-34 is found to be less stable than either AlPO₄-34F or AlPO₄-34h, which is consistent with the fact that AlPO₄-34 can only be prepared starting from AlPO₄-34F.