We derive an exact representation of the exchange-correlation energy within density functional theory (DFT) which spawns a class of approximations leading to correct long-range asymptotic behavior. Using a simple approximation, we develop an electronic structure theory that combines a new local correlation energy (based on Monte Carlo calculations applied to the homogeneous electron gas) and a ...

A large solvent polarity effect on the rate of singlet to triplet intersystem crossing (ksT) has been observed in the carbenes, diphenylcarbene (DPC) and dicycloheptadienylidene (DCHD)it is found that both ksT and the energy splitting (A&T) separtaing the singlet and triplet states decrease as the solvent polarity increases for the aromatic carbenes. This “inverse” gap effect, i.e. the time for...

The AM1ÈCI (Austin model 1 conÐguration interaction) method has been used to calculate energy gaps between the ground state and the lowest biradicaloid (BR) excited state as a measure for roughly (S 0) estimating the probability of reaching an conical intersection by bond twisting of one of the bonds S 0 ÈBR along the polymethine chain of unsymmetric cyanine dyes. Invoking qualitative concepts ...

in this work, the first in the world of science, the focus was on the best angle of connection between carbon nanotubes and the most widely used group of antibiotics. while having the highest stability, in terms of energy, we have the best angle of to connect to the in vivo delivery of intraoperative antibiotic binding with carbon nanotubes not lost. it will never work in the world of science. ...

It is usually assumed that the ground state lattice con"guration of polyacetylene is a dimerized chain. We found that the energy can be further reduced by an overall chain length contraction, which leads to a new bond length order parameter, in addition to the well-known bond alternation order parameter. For quasi-particles like solitons and polarons, these two order parameters are coupled with...

We report first-principles total-energy density-functional theory electronic structure calculations for the neutral and charge states of H intrinsic ~Frenkel pair! and extrinsic ~H vacancy or interstitial! point defects in KH2PO4. The relaxed atomic structures, the formation energy, the ionization energy, and electron and hole affinities for the various defects have been calculated. For the Fre...

All-electron static and time-dependent DFT electronic calculations, with complete geometrical optimization, are performed on tubular molecules up to C(210)H(20) that are finite sections of the (5,5) metallic single wall carbon nanotube with hydrogen termination at the open ends. We find pronounced C-C bond reconstruction at the tube ends; this initiates bond alternation that propagates into the...

The reactions of propenyl magnesium halides with ethylene were studied using ab initio calculations. The structure of the transition state and the ground state were evaluated and obtained the structural properties, theoretical thermodynamic and kinetic data i.e. rate constants of the reactions. The methods used for calculations are RHF, B3LYP and MP2 with 6-31G* b...

The electronic and structural properties of single wall carbon nanotubes (SWCNTs) interacted with 4-amino phenyl-azobenzene were theoretically investigated by using the hybrid DFT (hybrid-density functional theory) calculations. The amount of thermodynamic parameters of this reaction in the gas and aqueous phase suggesting thermodynamic favourability for adsorption of 4-amino phenyl-azobenzene ...

Simulations of defects in paramagnetic materials at high temperature constitute a formidable challenge to solid-state theory due to the interaction of magnetic disorder, vibrations, and structural relaxations. CrN is a material where these effects are particularly large due to a strong magnetolattice coupling and a tendency for deviations from the nominal 1:1 stoichiometry. In this work, we pre...