The random-phase approximation (RPA) for the electron correlation energy, combined with the exact-exchange (EX) energy, represents the state-of-the-art exchange-correlation functional within density-functional theory. However, the standard RPA practice--evaluating both the EX and the RPA correlation energies using Kohn-Sham (KS) orbitals from local or semilocal exchange-correlation functionals-...

A bstract We present the analytic formula for Energy-Energy Correlation (EEC) in electron-positron annihilation computed perturbative QCD to next-to-next-to-next-to-leading order (N 3 LO) back-to-back limit. In particular, we consider EEC arising from of an pair into a virtual photon as well Higgs boson and their subsequent inclusive decay hadrons. Our computation is based on factorization theo...

A fast method is developed for calculating the random phase approximation (RPA) correlation energy for density functional theory. The correlation energy is given by a trace over a projected RPA response matrix, and the trace is taken by a stochastic approach using random perturbation vectors. For a fixed statistical error in the total energy per electron, the method scales, at most, quadratical...

the electronic absorption spectral line shape of a diatomic molecule with harmonic potential curves is calculated using the time correlation function formalism. both the equilibrium shift and the frequency shift of the two linking electronic states ate taken into account. the spectrum is also calculated using the cumulated expansion which is related to the correlation function of the time-depen...

topological indices are the numerical value associated with chemical constitution purporting for correlation ofchemical structure with various physical properties, chemical reactivity or biological activity. graph theory is adelightful playground for the exploration of proof techniques in discrete mathematics and its results haveapplications in many areas of sciences. one of the useful indices ...

An accurate determination of the electron correlation energy is an essential prerequisite for describing the structure, stability, and function in a wide variety of systems. Therefore, the development of efficient approaches for the calculation of the correlation energy (and hence the dispersion energy as well) is essential and such methods can be coupled with many density-functional approximat...