In this paper, for the first time we have studied theoretically the effect of exchange-correlation holes around electrons in GaAlAs/GaAs/GaAlAs nanostructure on the temperature-dependent dynamic dielectric function of two-dimensional electron gas by employing random phase, STLS and Hubbard approximations. Also, we have investigated another interesting system which is coupled quantum wells struc...

The virial of the exchange potential in density functional theory yields the exchange energy, but the virial of the correlation potential does not yield the correlation energy. Via the adiabatic connection formula, we define a hypercorrelated potential whose virial is exactly the correlation energy. This exchange-correlation energy density is uniquely determined by the exchange-correlation ener...

We calculate, within the leading-order dynamical-screening approximation, the electron self-energy and spectral function at zero temperature for extrinsic (or gated/doped) graphene. We also calculate hot carrier inelastic scattering due to electron–electron interactions in graphene. We obtain the inelastic quasiparticle lifetimes and associated mean free paths from the calculated self-energy. T...

Local exchange-correlation functionals are defined for different systems with spherical symmetry, by requiring that they reproduce the correct exchange-correlation energy and exchange-correlation potential (up to a constant). For comparison, the results with the uniform electron gas local density approximation and a generalized gradient approximation are also shown. q 2000 Elsevier Science B.V....

We study nonlinear adiabatic connection paths in density-functional theory using modified electron–electron interactions that perform a long-range/short-range separation of the Coulomb interaction. These adiabatic connections allow us to define short-range exchange–correlation potentials and short-range local exchange–correlation energies per particle which we have calculated accurately for the...

The Kohn–Sham ~KS! solution is constructed from an accurate CI density and the KS exchange and correlation energies Ex and Ec , as well as the corresponding exchange and exchange-correlation energy densities ex(r) and exc(r), which are obtained for the hydrogen abstraction reaction H1H2 and the symmetrical four-center exchange reaction H21H2. The KS quantities are compared with those of the sta...

in this paper, the structural properties of the b30n20 molecule have been investigated at b3lyp/6-31g (d) level of theory. the optimized structure and electronic properties calculations for the studiedmolecule have been performed using gaussian 03 program. a mathematical equation of third degreewas exploited for the correlation and exchange energy with the number of primitives. the naturalbondi...

Foreign exchange market is one of the most complex dynamic market with high volatility, non linear and irregularity. As the globalization spread to the world, exchange rates forecasting become more important and complicated. Many external factors influence its volatility. To forecast the exchange rates, those external variables can be used and usually chosen based on the correlation to the pred...