In 2009 Odashima and Capelle (OC) showed a way to design a correlation-only density functional that satisfies a Lieb-Oxford bound on the correlation energy, without empirical parameters and even without additional theoretical parameters. However, they were only able to test a size-inconsistent version of it that employs total energies. Here, we show that their alternative size-consistent form t...

Because of its useful accuracy and efficiency, density functional theory (DFT) is one of the most widely used electronic structure theories in physics, materials science, and chemistry. Only the exchange-correlation energy is unknown, and needs to be approximated in practice. Exact constraints provide useful information about this functional. The local spin-density approximation (LSDA) was the ...

Ž . Ž . ABSTRACT: The local spin-density LSD functional and Perdew]Wang 91 PW91 generalized gradient approximations to atomization energies of molecules are investigated. We discuss the coupling-constant dependence of the atomization energy and why exchange errors of the functionals are greater than exchange]correlation errors. This fact helps to justify hybrid schemes which mix some exact exch...

This paper employs a general non-linear analysis tool to analyse the nature of time series associated with the price (returns) of a particular company in Tehran Stock Exchange. It is shown that the behavior of the process associated with the price (returns) time-series of this company is weakly chaotic, and due to the non-random behavior of the process, short term prediction of stock price is p...

The adsorption of benzene and C60 on graphene and boron nitride is studied using density functional theory with the van der Waals density functional (vdW-DF). By comparing these systems we can systematically investigate their adsorption nature and differences between the two functional versions vdW-DF1 and vdW-DF2. The bigger size of the C60 molecule makes it bind stronger to the surface than b...

Theoretically the Kohn-Sham band gap differs from the exact quasiparticle energy gap by the derivative discontinuity of the exchange-correlation functional. In practice for semiconductors and insulators the band gap calculated within any local or semilocal density approximations underestimates severely the experimental energy gap. On the other hand, calculations with an "exact" exchange potenti...

Two-dimensional T1-T2 H NMR relaxation correlation spectra and T2-T2 relaxation exchange spectra for samples of spruce wood across the full moisture content range from 0% to )100% are presented. The T1-T2 spectra unambiguously identify water in different environments within the wood that overlap in the corresponding and more traditional one-dimensional T1 or T2 experiment. The T2-T2 spectra una...

We study linear-response time-dependent density-functional theory (DFT) based on the singledeterminant range-separated hybrid (RSH) scheme, i.e. combining a long-range Hartree-Fock exchange kernel with a short-range DFT exchange-correlation kernel, for calculating electronic excitation energies of molecular systems. It is an alternative to the more common long-range correction (LC) scheme which...