The use of the FEFF8 code to calculate the XANES and electron density of states of some sulfides

Abstract

The FEFF8 was used to calculate x-ray absorption spectra (XANES) and the local partial electron density of states (LDOS) for several sulfides: InPS 4 (twice defective chalcopyrite), CdIn 2 S 4 (normal spinel) and Tl 3 AsS 3 (space group R3m). The calculated XANES are compared with experimental spectra. The self-consistent MTpotentials found for clusters of about 35 atoms were used to calculate XANES and LDOS for clusters of 87 atoms in the approach of full multiple scattering. In all cases the agreement of the simulated XANES and experimental ones is quite good. The theoretical LDOS agree well with the experimental x-ray emission K-and L 2,3 -spectra.

CdIn2S4 Nanotubes and “Marigold” Nanostructures: A Visible-Light Photocatalyst

“…6) is 1.90 eV, which is slightly lower than the experimentally determined value of 2.18 eV. [29] Given density functional theory usually underestimates bandgaps because of the discontinuity in the exchange-correlation potential, the calculated bandgap agrees well with the experimental value obtained from the UV-DRS (diffuse reflectance spectroscopy). From the local DOS (LDOS) of each atom (Fig.…”

“…Computational Details: All electronic structure calculations were carried out using VASP [29,31], which is based on density functional theory. The wave functions of the valence electrons were expanded using a plane wave basis set with a cutoff energy of 274.3 eV.…”

“…[30] All electronic structure calculations were carried out using the Vienna ab initio simulation package (VASP). [29,31,32] Table 1 shows a comparison of the photocatalytic activity of CdIn 2 S 4 prepared in water, methanol (Meth), ethylene glycol (EG), and aqueous PEG for hydrogen generation. An excellent photocatalytic activity was observed for the aqueous-and methanol-mediated CdIn 2 S 4 samples.…”

Chloride Ion Interactions with Oxide-Covered Aluminum Leading to Pitting Corrosion: A Review

“…Since the late 1980's a theoretical code FEFF, an ab initio, self-consistent, real-space multiple scattering code for calculating XANES, extended X-ray absorption fine structure (EXAFS), and local l-projected density of states (LDOS) for clusters of atoms, has been available for calculating theoretical spectra and this has greatly enhanced the analysis of XAS data. [107][108][109][110][111][112] With the release of newer versions of the FEFF code, it has become possible to carry out reliable calculations of the entire XAS spectra including the XANES, EXAFS, and the LDOS for clusters of atoms. The LDOS provides a direct interpretation of the experimental XANES spectra and an interpretation of the electronic structures that can give rise to the structural details observed in the experimental data.…”

Applications of X-Ray Transient Absorption Spectroscopy in Photocatalysis for Hydrogen Generation

“…XAFS spectra have been analyzed by commercially available software program packages (i.e., Athena, WinXAS, etc.) using starting structural parameters calculated from simulated structures or crystal structures of the molecule of interest by FEFF8.0 calculation, to obtain the scattering paths with the phases and amplitudes of the ground state [72,73]. The photoexcited transient-state spectrum was extracted according the Equation 7.4,…”