Point Defects Modeling Explains Multiple Sulfur Species in Sulfur-Doped Na₄(Al₃Si₃O₁₂)Cl Sodalite

Abstract

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First-principles Investigation of Electrides Derived from Sodalites

“…Recently, Stoliaroff et al have suggested that high concentrations of chlorine vacancies can be created by F-center point defects using DFT modeling 62 . It was found that ground and excited states of the singly occupied molecular orbital and the triply degenerate lowest unoccupied molecular orbital for the F-center 63 .…”

A Theoretical Discussion on the Stability of (O2)− and (S2)− Species in KCl and KBr Salts: Luminescence Spectra and Defect Energy Formation

“…Finally, it must be pointed out that at 𝜇 𝐸 𝐹 ~ 5 eV (the expected position of the Fermi level for KCl:S), four defects exhibit so low formation enthalpies that they are likely to be formed: VK, VCl, SCl and S2Cl. Their estimated computed concentrations for KCl grown at 1000K in S-rich atmosphere and quenched to room temperature are given in Table 1 (details on the computations of concentrations can be found has already been details in several publications 24,25 ). In these conditions, it can be seen that intrinsic vacancies will be the most common types of defects but SCl and (S2)Cl are in significant concentration.…”

“…Finally, it must be pointed out that at μ E F ∼ 5 eV (the expected position of the Fermi level for KCl:S), four defects exhibit very low formation enthalpies that they are likely to be formed: V K , V Cl , S Cl , and S 2Cl . Their estimated computed concentrations for KCl grown at 1000 K in the S-rich atmosphere and after being quenched to room temperature are given in Table (details on the computations of concentrations can be found in several publications , ).…”

“…24 Cl, and KCl materials, respectively). Consequently, such an entity has to be regarded, at least at the first sight, both as a flexible and a rigid entity that accepts different chemical environments but imposes to the solid in which it has embedded its constraints to relax toward its natural ground state with an oscillator frequency of ca.…”

The structural origin of the efficient photochromism in natural minerals

“…Due to composition and crystal structure similarities between the three minerals considered in this article, it has been assumed that this photochromic mechanism is the same for all of them. However, analysis of the oxidation states of sulfur in these minerals typically reveals a large variety of sulfur-based species ( 19 , 20 ), and we cannot rule out the possibility that the F-center can be generated from another sulfur impurity than S 2 2− . This will be investigated in the following by considering other sulfur impurities.…”