The response of an extended periodic system to a homogeneous field ~of wave-vector q50) cannot be obtained from a q50 time-dependent density functional theory ~TDDFT! calculation, because the RungeGross theorem does not apply. Time-dependent current–density functional theory is needed and demonstrates that one key ingredient missing from TDDFT is the macroscopic current. In the low-frequency li...

Article history: Received 19 April 2008 Received in revised form 2 June 2008 Accepted 15 July 2008 Available online 19 July 2008 PACS: 71.15.-m 71.15.Mb 71.15.Dx

We have studied the medium effects on the frequency-dependent polarizability of water by separating the total polarizability of water clusters into polarizabilities of the individual water molecules. A classical frequency-dependent dipole–dipole interaction model based on classical electrostatics and an Unsöld dispersion formula has been used. It is shown that the model reproduces the polarizab...

In this work we investigated by density functional theory (DFT)/time-dependent DFT (TDDFT) supramolecular complexes for photoinitiated electron collection, in particular [{(bpy)2Ru(dpp)}2RhCl2] and related catalysts derived by variation of the ligand/metal. The electron collection in this class of catalysts enables hydrogen production or DNA cleavage, among other applications. Changes in excita...

      In this article, the crystallization of polyethylene is investigated by the modified weighted density approximation. Also, a direct correlation function of polyethylene based on the RISM theory is used. The free energy of a polyethylene is calculated using the density functional theory. The crystallization and also the solid and liquid densities of polyethylene are calculated and compared...

in this work we use density functional theory based on the ultra-soft pseudo-potential to calculate thestructural, mechanical and thermal properties of narrow single walled bn, aln and gan nanotubes.the electron-electron interactions were expressed within the local density approximation (lda). wehave also obtained the phonon dispersion and elastic constants of these nanotubes using the densityf...