orrelation energy functional and potential from time-dependentexact-exchange theory

摘要

In this work we studied a new functional for the correlation energy obtained from theexact-exchange (EXX) approximation within time-dependent density functional theory. Correlationenergies have been calculated for a number of different atoms showing excellent agreement withresults from more sophisticated methods. These results lose little accuracy by approximating theEXX kernel by its static value, a procedure which enormously simplifies the calculations. Thecorrelation potential, obtained by taking the functional derivative with respect to the density, turnsout to be remarkably accurate for all atoms studied. This potential has been used to calculateionization potentials, static polarizabilities, and van der Waals coefficients with results in closeagreement with experiment.