Electronic and optical properties of Fe, Zn and Pb sulfides
Electronic and optical properties of Fe, Zn and Pb sulfides
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DOI：
10.1016/j.elspec.2005.01.019
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发表时间：
2005-05
影响因子：
1.4
通讯作者：
G. V. Oertzen;R. Jones;A. Gerson
中科院分区：
文献类型：
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作者：
G. V. Oertzen;R. Jones;A. Gerson
使用密度泛函理论（DFT）局域密度近似（LDA）和广义梯度近似（GGA）、Hartree-Fock（HF）方法和混合泛函B3LYP，对闪锌矿（ZnS）、黄铁矿（FeS2）和方铅矿（PbS）的空间和电子结构进行了从头计算。对于方铅矿，DFT LDA 和 GGA 泛函提供了带隙的最佳估计，范围在测量值的 −0.1 eV 到 +0.4 eV 范围内。 B3LYP 和 RHF 分别产生 +1.3 和 +5.4 eV 的误差。对于所有检查的泛函，晶胞参数误差在 -1.1% 和 +2.3% 之间变化。对于闪锌矿，B3LYP 函数提供了带隙的最佳估计（误差 +0.3 eV）。对于各种 DFT 泛函和 B3LYP，晶胞参数误差在 -2.1% 和 +2.0% 之间变化。 RHF 产生+3.8% 的误差。对于 FeS2，DFT-GGA 方法为晶胞和带隙提供了最佳结果。这可能是由于晶体场分裂力和能带分离力相互抵消，它们的大小相等但相反。计算出的导带态密度 (DOS) 用于解释使用同步加速器辐射获得的 S 1s XANES（X 射线吸收近边缘结构）光谱的实验特征。由于电子激发的 Δl= ±1 选择规则，S K 边缘 XANES 光谱代表 S 1s 电子到导带 S p 类轨道的跃迁。近边缘区域（超过边缘 15 eV）可以通过 DOS 很好地近似。 DOS 中的各个峰与 XANES 光谱中的峰相关。此外，介电函数的虚部反映了从占据能级到未占据能级的转变，并使用 DFT-GGA 形式对 XANES 的近边缘区域进行建模。使用介电函数可以很好地解析 XANES 光谱中的各个峰，特别是对于 ZnS 和 FeS2，而导带的 DOS 在预测所有三种矿物的 XANES 光谱形状方面更为成功。
Ab initio quantum-chemical calculations of the spatial and electronic structures of sphalerite (ZnS), pyrite (FeS2) and galena (PbS), using the density functional theory (DFT) local density approximation (LDA) and generalized gradient approximation (GGA), the Hartree–Fock (HF) method and the hybrid functional B3LYP, have been carried out. For galena, the DFT LDA and GGA functionals provided the best estimate of the band gap, from within −0.1 eV to +0.4 eV of the measured value. B3LYP and RHF gave rise to errors of +1.3 and +5.4 eV, respectively. The unit cell parameter error varied from between −1.1% and +2.3% for all the functionals examined. For sphalerite the B3LYP functional provided the best estimate of the band gap (error +0.3 eV). The unit cell parameter error varied between −2.1% and +2.0% for the various DFT functionals and B3LYP. RHF gave rise to an error of +3.8%. For FeS2, the DFT-GGA approach provides the best results for both the unit cell and the band gap. This may be due to mutual cancellation of the crystal field splitting and band separation force, which are of equal but opposite magnitudes. The calculated density of states (DOS) for the conduction band is used to interpret the experimental features of the S 1s XANES (X-ray absorption near-edge structure) spectra obtained using synchrotron radiation. Because of the Δl= ±1 selection rule for electron excitation, the S K-edge XANES spectra represent a transition of the S 1s electron to conduction band S p-like orbitals. The near-edge region, up to 15 eV past the edge is approximated well by the DOS. Individual peaks in the DOS correlate with peaks in the XANES spectra. In addition, the imaginary part of the dielectric function, which reflects the transitions from occupied to unoccupied levels, is used to model the near-edge region of the XANES, using the DFT-GGA formalism. Individual peaks in the XANES spectrum are moderately well resolved using the dielectric function, especially for ZnS and FeS2, while the DOS for the conduction band is more successful in predicting the shape of the XANES spectra for all three minerals.