density functional theory calculations were performed to investigate the interactions of nh3 molecules with tio2/mos2 nanocomposites in order to completely exploit the adsorption properties of these nanocomposites. given the need to further comprehend the behavior of the nh3 molecules oriented between the tio2 nanoparticle and mos2 monolayer, we have geometrically optimized the complex systems ...

This study presents a numerical assessment of total energy related physical quantities estimated using the orbital-specific (OS) global and range-separated hybrid functionals, designed to satisfy the linearity condition for orbital energies (LCOE). The numerical assessment demonstrates that accurate evaluation of the reaction energies, reaction barrier, and dissociation curve can be achieved vi...

The addition and abstraction reactions of OH radical with benzoate anion are investigated by density functional theory calculations that include solvent effects using UB3LYP, UCAM-B3LYP, UmPW1PW91 and UM06-2X functionals with the 6-311++G(2d,2p) basis set. Geometry optimizations of the reactants, products and transition state species are performed for the possible reaction paths. For the additi...

For the first time, a complete implementation of coupled perturbed density functional theory ~CPDFT! for the calculation of NMR spin–spin coupling constants ~SSCCs! with pure and hybrid DFT is presented. By applying this method to several hydrides, hydrocarbons, and molecules with multiple bonds, the performance of DFT for the calculation of SSCCs is analyzed in dependence of the XC functional ...

The present study deals with the solvent effect on the electronic spectra of 2,4-dihydroxy-5fluoropyrimidine i.e, the effect of polar solvents are ethanol, methanol, and water has been studied on the electronic transitions of the title molecule both experimentally and theoretically. The homo lumo analysis has been studied. Theoretical calculations are made with the help of Gaussian 03 by using ...

In order to investigate the selective catalytic reduction of NOx by hydrocarbons, Ag/Al2O3 models were constructed by means of density functional theory (DFT) and experimental results. The geometrical structures and vibrational frequencies obtained at B3LYP levels of DFT were compared with the corresponding experimental results. EXAFS results suggest silver ion species were predominant on the A...

Adsorption of NH3 and H2O molecules on pristine and B–doped Al12N12 nano–cage was investigated using density functional theory, by means of B3LYP and X3LYP functionals. Both NH3 and H2O molecules were found to bind to an Al atom of Al12N12 via chemisorption, releasing energies ranging from –1.48 to –1.53 and –1.16 to –1.22 eV, respectively. The binding energies of X3LYP functional are somewhat ...

The first systematic study of the CrðH2OÞ n ðnZ1K4Þ series of clusters is herein presented at the level of the unrestricted DFT B3LYP level in conjunction with electron core potential basis sets. The present structures are relevant for laser-induced and laser-ablation syntheses of chromium compounds, and also for fundamental spectroscopy studies of metal-bearing species in the gas phase. Calcul...

The accurate prediction of electronic and optical properties of molecules and solids is a persistent challenge for methods based on density functional theory. We propose a generalization of dielectricdependent hybrid functionals to finite systems where the definition of the mixing fraction of exact and semilocal exchange is physically motivated, nonempirical, and system dependent. The proposed ...

Density functional theory (DFT) calculations were performed to investigate adsorptions of vitamin C (Vit) on the surface a fullerene structure (Ful) in gaseous and water–solvated systems. Two models of Vit including OVit and MVit were created based on the original structure of Vit for OVit and methylation of all hydroxyl groups for MVit. All singular and hybrid structures were optimized and the...