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In this work, oxygen vacancies in MgAl2O4 crystal were investigated using the first-principles. The Heyd-Scuseria-Ernzerhof (HSE) was adopted to reproduce the experimental band gap. The finite-size correction scheme was applied to eliminate the unreal interaction between charged defects and their periodic images. Finally, taking into account of the electron-phonon coupling, we obtained the optical spectra of the F and F+ centres. The absorption peaks for the F and F+ centres are at 5.04 eV and 4.67 eV, respectively. Furthermore, we calculate the emission peak for the F centre is 3.28 eV. Comparing with the experimental results, the emission peak at 2.15 eV is related to the F+ centre. [ABSTRACT FROM AUTHOR]

In this paper, we present the optical spectra of the ZrO2 crystal containing oxygen vacancy based on the Density Functional Theory (DFT). The finite-size correction scheme (FNV) is employed to eliminate the artificial interactions and correct the defect formation energy of oxygen vacancies with three different charges (0, +1, +2). Besides, we use hybrid density functionals to relieve the band edge problem. Finally, we obtain the optical spectra for the F center and F + center containing the electron–phonon coupling. The absorption peak of F center of threefold coordinate oxygen vacancy (V O 3 ) near 446 nm (2.78 eV) agrees well with the experimental value (2.83 eV), which can enhance the visible light photocatalytic ability of ZrO2. The luminescence peak of the F + center of fourfold coordinate oxygen vacancy (V O 4 ) is 561 nm (2.21 eV), which is close to the experimental value (2.5 eV). [ABSTRACT FROM AUTHOR]

[Display omitted] • The experimental and theoretical FT-IR, FT-Raman spectra are performed to the structural characterization. • Thermodynamical properties and NCI interactions are studies. • The DFT and TD-DFT methods are used to investigate the effect of different solvents on the molecular properties. • Molecular docking study shows DMASBT may be a potential inhibitor of human folate receptors (4LRH). This manuscript reports Structural and spectroscopic analysis, solvent effect on the molecular properties and molecular docking of trans -2-(4-(dimethylamino) styryl)-benzothiazole. The ground state geometric structure of DMASBT is optimized at B3LYP/6-311++G level by means of the density functional theory. The experimental and computational FT-IR and FT-Raman spectra are performed to the structural characterization. Thermodynamical properties based on the frequency calculations are used to find entropy, internal energy, enthalpy and Gibbs free energy. The non-covalent interactions are studied to assess the positions and nature of noncovalent interactions. In addition, the influence of various solvents (gas phase, benzene, chloroform, ethanol, DMSO) effect in UV/Vis spectra, frontier molecular orbitals, molecular electrostatic potential surfaces, mulliken charges, nonlinear optical properties and Fukui functions are determined by using density functional theory method with B3LYP/6-311++G basis set. At last, molecular docking analysis is performed to understand the binding affinity and inhibition capability of DMASBT against 4LRH. [ABSTRACT FROM AUTHOR]

• Most stable and optimized molecular structure are done. • FT-IR and FT-Raman spectra are calculated by optimized structure and compared with obtained experimental results. • Gas phase, various polar and non-polar solvents are used to investigate the electronic solvation properties. • Molecular docking study are used to investigate ligand–6R3K protein interactions. In this present work, a chalcone derivative 1-(4-Chlorophenyl)-3-(4-ethoxyphenyl)-prop-2-en-1-one is investigated using the density functional theory. PES scan is used to find the most stable conformational structure of the title compound. The geometrical parameters, FT-IR and FT-Raman spectra are performed by the DFT method with B3LYP/6-311+G basis set, which are very comparable with the experimental results. UV-Vis spectrum, frontier molecular orbitals, global reactivity descriptors, molecular electrostatic potential surface, NLO parameters and Mulliken charge in the gas phase, various polar and non-polar solvents are performed to reveal solvents effect. Further, it is found that the electronic properties show a good correlation with the polarity of solvents. Hirshfeld Surface analysis demonstrates H···H contact is dominant in the crystal packing. By means of molecular reactivity descriptors such as natural bond orbital analysis, Fukui function and dual descriptor analysis, the chemical reactivity is theoretically estimated. ELF and LOL are used to access the energy density of electrons. Molecular docking illustrates ECC may be a potential inhibitor for 6R3K protein. [Display omitted] [ABSTRACT FROM AUTHOR]

The density functional theory with the Hubbard U parameter method was used to evaluate the lattice structure, electronic structures, and optical spectra of MgAl 2 O 4 crystals with cation vacancies. We analyzed the electronic structures of oxygen atoms around the cation vacancies. The holes prefers to distribute themselves on all the nearest oxygen atoms around the vacancy rather than to localize on a single oxygen atom. We propose the color center models V Mg 2 − − O 2 3 − 2 + and V Al 3 − − O 2 3 − 3 + for the magnesium vacancy and the aluminum vacancy with localized hole states. Taking into account electron-phonon coupling, we obtained the optical spectra of the cation vacancies with localized hole states. The calculated absorption peaks of the cation vacancies with localized hole states are consistent with the experimental results. The emission peaks of the magnesium vacancy and the aluminum vacancy with localized hole states are at 2.63 eV and 2.62 eV, close to that of the F center at 2.69 eV. We predict that cation vacancies with localized hole states will act as a source of blue luminescence. • The DFT+U method was used to evaluate the electronic structures and optical spectra of MgAl 2 O 4 crystals with cation vacancies. • The color center models V Mg 2 − − O 2 3 − 2 + and V Al 3 − − O 2 3 − 3 + are proposed for a magnesium vacancy and an aluminum vacancy with localized hole states. • Cation vacancies with localized hole states are predicted to act as a source of blue luminescence. [ABSTRACT FROM AUTHOR]

A large OSL (optically stimulated luminescence) response from copper replacing lithium (Cu Li) in lithium aluminate (LiAlO 2 , LAO) has been reported in earlier studies, and the origin of the OSL response was isolated Cu Li. However, other trapped-hole centers that are not involved in OSL response, such as Cu Li –V Li and STH (self-trapped hole center, a hole localized at O ion adjacent to V Li), also appear in LiAlO 2 :Cu crystal after irradiation. To reach optimum OSL response of LAO crystal, a comprehensive analysis that integrates first-principles and thermodynamic calculations is employed to investigate the relative stability of intrinsic defects and Cu defects. Defect formation energies (DFE) of these defects are obtained from density functional theory (DFT), as well as corrected by finite-size corrections (FNV). To find the region of Fermi level where the crystal maintains electrical neutrality, we combine DFEs as a function of Fermi level for Cu defects and intrinsic defects to discuss the charge compensation mechanism. Then, the definite DFEs for these defects and the energetically preferred sites for substitutional Cu ions are shown after determining the locations of Fermi levels under different conditions. In O-rich conditions, the results show that Cu Al is most stable with the decrease of the chemical potential of Al. Furthermore, Cu Li is energetically preferred under O-poor conditions, and DFE of isolated Cu Li is much lower than other Cu defects, thus, the optimum OSL signal occurs. To validate our conclusions, we also present the deformation charge density to study the chemical bonds of Li–O, Al–O, Cu Li –O and Cu Al –O. The results also suggest that it would cost more energy to destroy Al–O bond than Li–O bond. • DFEs are corrected by finite-size corrections. • Determine the stable range of LAO by thermodynamic calculations. • In O-poor conditions, Cu Li is most stable, and optimum OSL signal occurs. • In O-rich conditions, Cu Al is energetically preferred with the decrease of μ A l . [ABSTRACT FROM AUTHOR]

• Alkauskas' method is employed to relieve the band edge problem. • The defect formation energy is aligned with the finite-size correction (FNV). • The point defect Vo2+ is relative stable in most situations. • The electron-phonon coupling during the optical transition process is calculated. • F center and F+ center play an indispensable role in luminescence and absorption. To obtain more accurate optical properties, we optimize the oxygen vacancy in gamma-LiAlO 2 with three different charges (0, +1, +2) to study the optical spectrum line shapes of the oxygen vacancy, and the defect formation energies are corrected by finite-size correction scheme (FNV). We obtain the optical spectra containing electron-phonon coupling. The absorption spectra of the F center and F+ center peak at 4.6 eV and 5.5 eV, which are close to the experimental result. So we predicate that the absorption band peak at 5.21 eV should be the origin of the F+ center. The luminescence peaks of the F center and F+ center are at 2.98 eV and 2.56 eV, respectively. Comparing with the experimental results, the emission peak (3.02 eV) is caused by the F center. [ABSTRACT FROM AUTHOR]