Density functional theory(DFT) and Hartree-Fock(HF) calculations are reported for the family of transition metal fluorides ScF3, TiF4, VF5, and CrF6. Both HF and the local-density-aproximation (LDA) yield excellent agreement with experimental bond lengths, while the B-LYP gradient-corrected density functional gives bond lengths 0.04 − 0.05 Å too long. An investigation of various combinations of...

This paper addresses the recent development of a series of linear-scaling electronic structure calculation methods [1-9], which are based on the divide-and-conquer (DC) method by Yang et al. [11,12]. The DC method used to be applied mainly to pure density functional theory (DFT) or semi-empirical molecular orbital (MO) calculations. We have applied the DC method to the Hartree-Fock (HF) and hyb...

The influence of changes in the contracted Gaussian basis set used for ab initio calculations of nuclear magnetic resonance (NMR) phosphorous chemical shift anisotropy (CSA) tensors was investigated. The isotropic chemical shift and chemical shift anisotropy were found to converge with increasing complexity of the basis set at the Hartree-Fock (HF) level. The addition of d polarization function...

The gate defect of the ferroelectric HfO 2 -based Si field-effect transistor (Si FeFET) plays a dominant role in its reliability issue. first-principles calculations are an effective method for atomic-scale understanding defects. However, study on defects FeFET stacks, i.e., metal/orthorhombic-Hf 0.5 Zr O /SiO x /Si structure, has not been reported so far. key challenge is construction stack mo...

We present in this paper the general framework of a method which permits to restore the rotational and particle number symmetries of wave functions obtained in Skyrme HF+BCS calculations. This restoration is nothing but a projection of mean-field intrinsic wave functions onto good particle number and good angular momentum. The method allows also to mix projected wave functions. Such a configura...

Within an ab–initio HF scheme, we use both Berry–phase calculations and supercell calculations in order to compute the dynamical charges for lattice dynamics and the electronic dielectric constant for KNbO3 and BaTiO3. Comparison with experimental data indicates that HF provides a description of the electronic properties of this material whose accuracy is of the same order as the LDA one. There...

Studies of compression modes of nuclei are of particular interest since their strength distributions, S(E), are sensitive to the value of the nuclear matter incompressibility coefficient, K [1]. At present, Hartree-Fock (HF) based random-phase-approximation(RPA) calculations for the isoscalar giant monopole resonance (ISGMR) reproduce the experimental data for effective interactions associated ...

Structural and magnetic properties of purine and pyrimidine nucleotides (CMP, UMP, dTMP, AMP, GMP, IMP) were studied at different levels of ab initio molecular orbital theory. These calculations were performed at the hartree-fock level and density functional B3LYP methods. Geometries were fully optimized by following Cs symmetry restrictions. The standard 6-31G** basis set which includes polari...