We have studied the electron exchange-correlation effect on thecharacteristics of the two-component unmagnetized dense quantum plasma withstreaming motion. For this purpose, we have used the quantum hydrodynamic model(including the effects of a quantum statistical Fermi electron temperature) for studyingthe propagation of an electrostatic electron plasma waves in such th...

“Nonfreeness” is the (negative of the) difference between the von Neumann entropies of a given many-fermion state and the free state that has the same 1-particle statistics. It also equals the relative entropy of the two states in question, i.e., it is the entropy of the given state relative to the corresponding free state. The nonfreeness of a pure state is the same as its “particle-hole symme...

The potential energy surface of the Fe dimer is investigated on the basis of density functional theory in the generalized gradient approximation (GGA). Electron correlation effects are taken into account explicitly within the GGA+U approach. We find a value of 2.20 eV for the Coulomb repulsion parameter U to describe the Fe dimer best, yielding a 9 Sigma(g)- ground state with an interatomic sep...

Following absorption of a single photon, angles of simultaneous emission of two electrons from a He n S atom become more correlated with increasing n. We find that the strength of this correlation is due to the two-electron continuum of the electron-impact ionization of the He+ ns ion. The strength is determined by the width of the momentum profile of the ionic ns state but not the strength of ...

Abstract: I show that there exists a class of inequalities between correlation functions of different orders of a chaotic electron field. These inequalities lead to the antibunching effect and are a consequence of the fact that electrons are fermions – indistinguishable particles with antisymmetric states. The derivation of the inequalities is based on the known form of the correlation function...

Calculation of electron correlation energy in molecules involves a very important computational effort, even in the simplest cases. Nowadays, using the new parallel libraries (PETSc and SLEPc) and MPI, we can resolve this calculation faster and with very big molecules. This result is a very important advance in chemical computation.

Electron correlation effects in Fe are analysed using a first-principles linear combination of atomic orbitals scheme. In our approach, we first use a local orbital density functional solution to introduce a Hubbard Hamiltonian without fitting parameters. In a second step, we introduce a many-body solution to this Hamiltonian using a dynamical mean-field approximation. Our analysis shows that m...

s It is suggested that simple electronic shielding effects induced by wave function antisymmetrization tend to govern the energy ordering of singlet and triplet terms within a two-electron atomic configuration. This approach gives rise to the following alternating rule: For the term of greatest orbital angular momentum within a configuration, the triplet lies below the singlet. The energy order...

Measurements of polarization-dependent soft x-ray absorption reveal that the electronic states determining the low-energy excitations of NaxCoO2 have predominantly a(1g) symmetry with significant O 2p character. In contrast to the prediction of band theory, doping-dependent O 1s x-ray absorption shows a large transfer of spectral weight, providing spectral evidence for strong electron correlati...