Theoretical results for giant resonances in the three doubly magic exotic nuclei Ni, Sn and Sn are obtained from Hartree-Fock (HF) plus Random Phase Approximation (RPA) calculations using the D1S parametrization of the Gogny two-body effective interaction. Special attention is paid to full consistency between the HF field and the RPA particle-hole residual interaction. The results for the exoti...

A method for calculating the dispersion energy between molecules modeled with the general effective fragment potential (EFP2) method and those modeled using a full quantum mechanics (QM) method, e.g., Hartree-Fock (HF) or second-order perturbation theory, is presented. C(6) dispersion coefficients are calculated for pairs of orbitals using dynamic polarizabilities from the EFP2 portion, and dip...

The temperature dependence of conductance resonances is used to measure the evolution with the magnetic field of the average level spacing ∆ǫ of a droplet containing ∼ 30 electrons created by lateral confinement of a twodimensional electron gas in GaAs. ∆ǫ becomes very small (< 30μeV) near two critical magnetic fields at which the symmetry of the droplet changes and these decreases of ∆ǫ are pr...

Kohn–Sham (KS) and Hartree–Fock (HF) determinants were used as the true many-body wave functions for calculations of molecular energies, vibrational frequencies, and excited electronic states. The results justified common practice, encountered in the sum over states theories, in which these two determinants are used as the first-order approximation of the wave function. However, a distinct beha...

Asymmetric I /V curves with respect to the polarity of the voltage bias were observed in the Hg /Au junctions containing bilayers of alkanethiols of different chain length. A larger current resulted when a negative bias was applied to the metal carrying a longer chain alkanethiol monolayer. This behavior is simulated using a single molecule junction model, within the frameworks of the extended ...

Uma sequência hierárquica de conjuntos de bases de contração segmentada para todos os elétrons de qualidades dupla, tripla e quádrupla zeta de valência mais funções de polarização aumentadas com funções difusas para os átomos de H a Ar foi desenvolvida. Um estudo sistemático dos conjuntos de bases necessários para obter valores confiáveis e precisos de polarizabilidades de dipolo estáticas de a...

A comparative systematic study of the CrO2F2 compound has been performed using different conventional ab initio methodologies and density functional procedures. Two points have been analyzed: first, the accuracy of results yielded by each method under study, and second, the computational cost required to reach such results. Weighing up both aspects, density functional theory has been found to b...

We present a physically motivated correlation functional belonging to the meta-generalized gradient approximation (meta-GGA) rung, which can be supplemented with long-range dispersion corrections without introducing double-counting of correlation contributions. The functional is derived by the method of constraint satisfaction, starting from an analytical expression for a real-space spin-resolv...

The Impulse Compton Profiles (CP’s) J(q) and the 〈pn〉− expectation values for some inert gas atoms(He-Kr) are computed and compared within the Harbola-Sahni (HS), Hartree-Fock (HF) theories and a Self Interaction Corrected (SIC) density functional model. The Compton profiles for excited states of Helium atom are also calculated. While the calculated CP’s are found to generally agree, they diffe...

The modeling of dispersion interactions in density functional theory (DFT) is commonly performed using an energy correction that involves empirically fitted parameters for all atom pairs of the system investigated. In this study, the first-principles-derived dispersion energy from the effective fragment potential (EFP) method is implemented for the density functional theory (DFT-D(EFP)) and Har...