In: Tetrahedron, 2006, vol. 62, no. 48, p. 11106-11111
A new 1,3-dithiol-2-ylidene substituted naphthopyranone 2 has been synthesized and characterized. UV–vis spectroscopic and cyclic voltammetry results, interpreted on the basis of density functional theory, show that 2 displays an intramolecular charge-transfer transition and acts like a donor–acceptor (D–A) system. Furthermore, a weak fluorescence originating from the excited...
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In: Chemical Physics Letters, 2006, vol. 427, no. 4-6, p. 449-454
Using a DFT based Ligand Field treatment (LFDFT) of the electronic structure of Co(II) and Cu(II) porphyrins (CoP and CuP) we analyse the origin of their EPR spectra. From a comparison between theoretical result on Co model clusters (CoP and CoP–ZnP dimer) we conclude that the g-tensor values are very sensitive to the axial coordination which stabilizes a ²A₁ ground state in good...
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In: Chimia, 2006, vol. 60, no. 4, p. 228-230
Energetics and the electronic structure of various types of single-walled carbon nanotubes have been investigated by using Density Functional Theory. Armchair [n,n], zigzag [n,0] and chiral [n,m] C₄₀H₂₀ nanotubes have been considered. Calculations show that the armchair isomer is the most stable among the three types and they further reveal the factors that stabilize this isomer....
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In: Comptes Rendus Chimie, 2006, vol. 9, no. 2, p. 226-239
An account of the performance of a modern and efficient approach to Density Functional Theory (DFT) for the prediction of the photophysical behavior of a series of Ru(II) and Os(II) complexes is given. The time-dependent-DFT method was used to interpret their electronic spectra. Two different types of compounds have been analyzed: (1) a complex undergoing a light induced isomerization of one of...
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In: Journal of Molecular Structure: THEOCHEM, 2006, vol. 762, no. 1-3, p. 93-10
In this work we apply in a systematic way our multi-determinantal model to calculate the fine structure of the whole atomic multiplet manifold. The key feature of this approach is the explicit treatment of near-degeneracy correlation using ad hoc configuration interaction (CI) within the active space of Kohn–Sham (KS) orbitals with open d- or f-shells. The calculation of the CI-matrices is...
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In: The Journal of Chemical Physics, 2006, vol. 124, p. 214105
Recently, linear scaling construction of the periodic exact Hartree-Fock exchange matrix within the Γ-point approximation has been introduced [J. Chem. Phys. 122, 124105 (2005)]. In this article, a formalism for evaluation of analytical Hartree-Fock exchange energy gradients with respect to atomic positions and cell parameters at the Γ-point approximation is presented. While the...
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In: Journal of Chemical Theory and Computation, 2006, vol. 2, no. 4, p. 1106-1111
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In: Journal of Physics: Condensed Matter, 2006, vol. 17, p. 7995-8003
The electronic and magnetic properties of both LaCoO₃ and La0.5Ca0.5CoO₃ have been investigated by means of ab initio full-potential augmented plane wave plus local orbitals (APW+lo) calculations carried out with the Wien 2k code. The functional used is the local-density approximation LDA +U. Doping with Ca²⁺ introduces holes into the Co–O...
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In: The European Physical Journal B, 2005, vol. 45, no. 4, p. 455-458
We present first-principles calculations for the optical properties of germanium dioxide in the rutile structure. The electronic band structure has been calculated self-consistently within the local density approximation using the full-potential linearized augmented plane wave method. The electronic band structure shows that the fundamental energy gap is direct at the center of the Brillouin...
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In: The European Physical Journal B, 2005, vol. 44, no. 3, p. 281-286
The electronic and optical properties of tantalum carbide TaC have been calculated using the full-potential linearized augmented-plane-wave method within the local density approximation scheme for the exchange-correlation potential. We find that the optical spectra can be extremely sensitive to the Brillouin zone sampling. The influence of relativistic effects on the dielectric function is...
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