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Este trabajo aborda el estudio de los taninos condensados (proantocianidinas) de Ephedra frustillata Miers. Se estudiaron comparativamente los extractos metanólicos de los tallos aéreos herbáceos y lignificados proven...

In this thesis we present contributions in the field of the applications of quantum field theories techniques to condensed matter models. In chapter 3 we investigate on the non covariant fermionic determinant and its c...

Abstract This book provides a practical guide to molecular dynamics and Monte Carlo simulation techniques used in the modelling of simple and complex liquids. Computer simulation is an essential tool in studying the chem...

There are few phenomena in condensed matter physics that are defined only by the fundamental constants and do not depend on material parameters. Examples are the resistivity quantum, h/e2 (h is Planck's constant and e th...

First-principles simulation, meaning density-functional theory calculations with plane waves and pseudopotentials, has become a prized technique in condensed-matter theory. Here I look at the basics of the suject, give a...

The field of phase transitions and critical phenomena continues to be active in research, producing a steady stream of interesting and fruitful results. It has moved into a central place in condensed matter studies. Stat...

We present an analysis of the performances of a parameter free density functional model (PBE0) obtained combining the so called PBE generalized gradient functional with a predefined amount of exact exchange. The results ...

We present ab initio quantum-mechanical molecular-dynamics calculations based on the calculation of the electronic ground state and of the Hellmann-Feynman forces in the local-density approximation at each molecular-dyna...

Generalized gradient approximations (GGA's) seek to improve upon the accuracy of the local-spin-density (LSD) approximation in electronic-structure calculations. Perdew and Wang have developed a GGA based on real-space c...

Langreth and Mehl (LM) and co-workers have developed a useful spin-density functional for the correlation energy of an electronic system. Here the LM functional is improved in two ways: (1) The natural separation between...

A correlation-energy formula due to Colle and Salvetti [Theor. Chim. Acta 37, 329 (1975)], in which the correlation energy density is expressed in terms of the electron density and a Laplacian of the second-order Hartree...

We present an efficient scheme for calculating the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set. In the first part the application of Pulay's DIIS method (direct inversion ...

PACS number(s)

The model and theoretical understanding of the Raman spectra in disordered and amorphous carbon are given. The nature of the G and D vibration modes in graphite is analyzed in terms of the resonant excitation of \ensurem...

An approach for electronic structure calculations is described that generalizes both the pseudopotential method and the linear augmented-plane-wave (LAPW) method in a natural way. The method allows high-quality first-pri...

QUANTUM ESPRESSO is an integrated suite of computer codes for electronic-structure calculations and materials modeling, based on density-functional theory, plane waves, and pseudopotentials (norm-conserving, ultrasoft, a...

Materias / palabras clave: Neutron diffraction; Magnetic structure; Diffraction; Neutron scattering; Powder diffraction; Materials science; Computational physics; Physics; Scattering; Nuclear magnetic resonance; Optics; Magnetic field

The exact density functional for the ground-state energy is strictly self-interaction-free (i.e., orbitals demonstrably do not self-interact), but many approximations to it, including the local-spin-density (LSD) approxi...

A new approach to the construction of first-principles pseudopotentials is described. The method allows transferability to be improved systematically while holding the cutoff radius fixed, even for large cutoff radii. No...

35 pages, 8 figures.-- Printed version published on Mar 25, 2002.-- ArXiv pre-print available at: http://arxiv.org/abs/cond-mat/0111138

Materias / palabras clave: magnetism, solid state physics, superconductivity, properties of composites and alloys, quantum properties of condensed matters; Science: Physics

Materias / palabras clave: soft matter, computer simulations, solids, phase transformations, liquid systems, amorphous systems; Science: Physics

Materias / palabras clave: condensed matter physics, superconductivity; Science: Physics

Materias / palabras clave: soft condensed matter, biophysics, glass, polymers and plastics, colloid and surface chemistry; Science: Chemistry; Medicine: Medicine (General): Medical physics. Medical radiology. Nuclear medicine; Technology: Chemical...