The Electronic Structure of the Isoelectronic, Square-Planar Complexes [FeII(L)2]2-and [CoIII(LBu)2]-(L2-and (LBu)2-= Benzene-1,2-dithiolates):  An Experimental and Density Functional Theoretical Study

We report routes towards synthesis of novel [Formula: see text]-conjugated freebase cobalt, copper, gallium and manganese meso-alkynylcorroles. UV-vis spectra show that extensive peak broadening, red shifts, and changes in the oscillator strength of absorptions increase with the extension of [Formula: see text]-conjugation. Using density functional theory (DFT), we have carried out a first theoretical study of the electronic structure of these metallocorroles. Decreased energy gaps of about 0.3–0.4 eV between the HOMO and LUMO orbitals compared to the corresponding copper, gallium and manganese meso-5,10,15 triphenylcorrole are observed. In all cases, the HOMO energies are nearly unperturbed as the [Formula: see text]-conjugation is expanded. The contraction of the HOMO–LUMO energy gaps is attributed to the lowered LUMO energies.

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Theoretical study on the electronic structure, mechanical property, and thermal expansion of yttrium oxysulfide

International Journal of Computational Materials Science and Engineering ◽

10.1142/s2047684115500049 ◽

2015 ◽

Vol 04 (01) ◽

pp. 1550004

Author(s):

Ruipeng Gao ◽

Yefei Li

Keyword(s):

Mechanical Property ◽

Thermal Expansion ◽

Electronic Structure ◽

Bulk Modulus ◽

Density Functional ◽

Theoretical Study ◽

Spherical Shape ◽

Weak Anisotropy ◽

Covalent Bonds ◽

Very High

The electronic structure, mechanical property and thermal expansion of yttrium oxysulfide are calculated from first-principles using the theory of density functional. The calculated cohesive energy indicates its thermodynamic stable nature. From bond structure, the calculated bandgap is obtained as 2.7 eV; and strong covalent bonds exist between Y and O atoms intra 2D [ Y – O ] layer in material, while relatively weak covalent bonds also exist inter 2D [ Y – O ] layer and S atoms. From simulation, it is found that the bulk modulus is about 119.4 GPa for the elastic constants, and the bulk modulus shows weak anisotropy because the surface contours of them are close to a spherical shape. The calculated B/G clearly implies its ductile nature, and the Y 2 O 2 S phase can also be compressed easily. The temperature dependence of thermal expansions is mainly caused by the restoration of thermal energy due to lattice excitations at low temperature. When the temperature is very high, the thermal expansion coefficient increases linearly with temperature increasing. Meanwhile, the heat capacities are also calculated and discussed by thermal expansion and elasticity.

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Theoretical Study of the Electronic Structures of Li-Doped ZnO

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.535-537.214 ◽

2012 ◽

Vol 535-537 ◽

pp. 214-218

Author(s):

Qi Xin Wan ◽

Jia Yi Chen ◽

Zhi Hua Xiong ◽

Dong Mei Li ◽

Bi Lin Shao ◽

...

Keyword(s):

Electronic Structure ◽

Density Functional ◽

Formation Energy ◽

Lattice Distortion ◽

Theoretical Study ◽

Functional Theory ◽

Li Doping ◽

The Density Functional Theory ◽

Doped Zno ◽

Good Agreement

The first-principles with pseudopotentials method based on the density functional theory was applied to calculate the geometric structure, the formation energy of impurities and the electronic structure of Li-doped ZnO. In the system of Li-doped ZnO, LiZn can not result in lattice distortion. In contrast with that case, LiO and Lii result in lattice distortion after Li doping in ZnO. In Li-doped ZnO, LiO is the most unstable than the other cases. Simultaneously, Lii is more stable than LiZn according to that Lii has smaller formation energy. Furthermore, the electronic structure of Li-doped ZnO indicates that that LiZn behaves as acceptor, while Lii behaves as donor. In conclusion, in Li-doped ZnO, Lii is always in the system to compensate the acceptor. Singly doping Li in ZnO is difficult to gain p-ZnO for the self-compensation. The results are in good agreement with other calculated and experimental results.

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