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Université de Fribourg

Calculation of spin-orbit coupling within the LFDFT: Applications to [NiX₄]²⁻ (X=F⁻, Cl⁻, Br⁻, I⁻)

Atanasov, Mihail ; Rauzy, Cédrick ; Baettig, Pio ; Daul, Claude A.

In: International Journal of Quantum Chemistry, 2005, vol. 102, p. 119-131

Spin-orbit coupling has been introduced into our newly developed ligand field density functional theory (LFDFT), using the zero-order regular approximation as implemented into the Amsterdam density functional (ADF) code. Application of the formalism to a series of NiX₄²⁻ (X=F⁻, Cl⁻, Br⁻, I⁻) compounds shows the increasing importance of intra-ligand spin-orbit coupling across the F,...

Université de Fribourg

Assessment of theoretical prediction of the NMR shielding tensor of ¹⁹⁵PtClxBr6–x²⁻ complexes by DFT calculations: experimental and computational results

Penka Fowe, Emmanuel ; Belser, Peter ; Daul, Claude A. ; Chermette, Henry

In: Physical Chemistry Chemical Physics, 2005, vol. 7(8), p. 1732-1738

In the present work, the ZORA spin–orbit Hamiltonian, in conjunction with the gauge including orbital (GIAO) method based on DFT theory has been used to calculate ¹⁹⁵Pt chemical shift of ¹⁹⁵PtClxBr6–x²⁻ complexes. Excellent agreement with experiments has been obtained for calculations bearing on optimized geometries and all electrons triple zeta +...

Université de Fribourg

Evaluation of two-electron integrals including the factors rk₁₂exp(−γr²₁₂) over Cartesian Gaussian functions

Weber, Valéry ; Daul, Claude A.

In: Computer Physics Communications, 2004, vol. 158 (1), p. 1-11

We present a practical scheme for the evaluation of nonstandard two-electron integrals including the factors rk₁₂exp(−γr²₁₂) which have been appeared recently, where k>=-1 is an integer. The method used throughout this paper is based on the highly efficient Head-Gordon and Pople (HGP) approach of evaluation of electron repulsion integrals (ERI). Thus only straightforward...

Université de Genève

Le rôle de l'activité microbienne dans la cimentation précoce des beachrocks (sédiments intertidaux)

Neumeier, Urs ; Davaud, Eric (Dir.) ; Bernier, Paul (Codir.)

Thèse de doctorat : Université de Genève, 1998 ; Sc. 2994.

Les beachrocks sont formés en quelques dizaines d'années dans la zone intertidale par la cimentation précoce des sédiments de plage. Pour comprendre les mécanismes responsables de la diagenèse, les ciments ont été étudiés en détail, la composition de l'eau interstitielle a été analysée, et un modèle a été développé pour simuler la formation de beachrock. Celui-ci permet de...

Université de Fribourg

Radial numerical integrations based on the sinc function

Weber, Valéry ; Daul, Claude A. ; Baltensperger, Richard

In: Computer Physics Communications, 2004, vol. 163(3), p. 133-142

An algorithm for the generation of adaptive radial grids used in density functional theory or quantum chemical calculations is described. Our approach is general and can be applied for the integration over Slater or Gaussian type functions with only minor modifications. The relative error of the integration is fully controlled by the algorithm within a specified range of exponential parameters...

Université de Fribourg

The calculation of ESR parameters by density functional theory: the g- and A-tensors of Co(acacen)

Atanasov, Mihail ; Baerends, Evert Jan ; Baettig, Pio ; Bruyndonckx, Raf ; Daul, Claude A. ; Rauzy, Cédrick ; Zbiri, Mohamed

In: Chemical Physics Letters, 2004, vol. 399(4-6), p. 433-439

The new DFT based ligand field (LF) model is proposed to calculate the g- and A-tensors of [Co(acacen)] that is known to be a difficult case. The results obtained are compared with the ZORA approach implemented in ADF as well as with the experimental values. The calculations are in good agreement with the experimental data and demonstrate the ability of the method to reproduce the large...

Université de Fribourg

FP-LAPW investigation of electronic structure of TaN and TaC compounds

Sahnoun, Mohammed ; Daul, Claude A. ; Driz, Mohamed ; Parlebas, J.C. ; Demangeat, C.

In: Computational Materials Science, 2005, vol. 33(1-3), p. 175-183

We study the structural and electronic properties of tantalum compounds, i.e. TaC and TaN, by means of accurate first principle total energy calculations using the full-potential linearized augmented plane wave plus local orbitals (FP-LAPW + lo) method. The calculations are based on density functional theory and we use the local density approximation (LDA) as well as the generalized gradient...

Université de Fribourg

Full potential calculation of structural, electronic and optical properties of KMgF₃

Sahnoun, Mohammed ; Zbiri, Mohamed ; Daul, Claude A. ; Khenata, R. ; Baltache, H. ; Driz, M.

In: Materials Chemistry and Physics, 2005, vol. 91(1), p. 185-191

A theoretical study of the structural, electronic and optical properties of KMgF₃ is presented using the full-potential linearized augmented plane wave method (FP-LAPW). In this approach, the local density approximation was used for the exchange-correlation potentials. First, we present the main features of the structural and electronic properties of this compound, where the electronic band...

Université de Fribourg

Intracellular vesicle transport in "Arabidopsis thaliana" : functional characterization of the t-SNARE homologue AtSNAP33

Wick, Peter ; Sticher, Liliane (Dir.)

Thèse de doctorat : Université de Fribourg, 2002 ; no 1386.

The secretory pathway is a complex endomembrane system essential for all eukaryotic cells. It transports proteins to the extracellular space or to the vacuole. All proteins which are secreted are synthesized at the endoplasmic reticulum (ER) and have a signal peptide in common. The signal peptide is necessary for the transport into the lumen of the ER where the correct folding of the protein...