Conventional density functional theory DFT fails for materials with strongly correlated electrons, such as late transition metal oxides. Large errors in the intra-atomic Coulomb and exchange interactions are the source of this failure. The DFT+U method has provided a means, through empirical parameters, to correct these errors. Here, we present a systematic ab initio approach in evaluating the ...

in this study, the interaction between no2+ cation and hen (n = 1-7) clusters is investigated by means of ab initio calculations at mp2/aug-cc-pvtz and qcisd/aug-cc-pvtz computational levels. the first and second solvation shells were obtained while n atom of no2+ interacts with five and two he atoms, respectively. stabilization energies of the studied complexes including basis set superpositio...

an ab initio and density functional theory (dft) study about conformational analysis of tripeptide model hco−gly−l−ile−gly−nh2 is presented. the tripeptide was scanned about initial, central, and final residues, separately while for every scanning procedure the two other residues had been kept in the β conformation and side chain (sc) dihedral angles were maintained on the gauche− (g‾) state (χ...

the results of mndo, am1 and pm3 semi-empirical calculations and hf/6-31g*, mp/6-31g*, mp2/6-311+g**, and b3lyp/6-311g** and qcisd/6-31g* ab initio methods for angle strain and conjugation effects in twist-boat, boat, and half-chair geometries of (z,z,z)-cycloocta-1,3,5-triene indicate that all methods, except pm3, predict wrong ordering of the conformations.

ab initio calculations at hf/6-31g* level of theory for geometry optimization and mp2/6-31g*//hf/6-31g*for total energy calculation are reported for z-cyclooctene (1). the most favorable conformation of 1 is theunsymmetric boat-chair (1-bc) geometry. potential energy profiles for two different boat-chair/boat-chairinterconversion processes were calculated. the process via a chair transition sta...

We review the young field of ab initio molecular dynamics applied to molecule-surface reactions. The techniques of ab initio molecular dynamics include methods that use an analytic potential energy function fit to ab initio data and those that are fully ab initio. In this review, we focus on the insights provided by ab initio-based molecular dynamics that are currently unavailable from experime...

: in this work, different levels of theory containing hf, b3lyp, and mp2 with different basis sets such as 6-31g, 6-31g*, 6-311g, 6-311+g, 6-31+g*, 6-31+g are used to predict relative acidity constants of some aniline derivatives. three different kinds of radii containing uahf, bondi, and pauling are used to study how cavity forms change acidity constants. in all cases, dpcm model is used to si...

in this study, b12n12 nano ring has been selected because it consist of four 6-side rings and polar bonds b-n which in comparison with non-polar bonds c-c, is more suitable for the study of the absorption of other compounds. so reactivity and stability of benzene alone and in the presence b12n12 nano ring field checked. to determine the non-bonded interaction energies between benzene and b12n12...

the intermolecular forces between water molecules are of great importance in many areas of chemistry including solvation, solution chemistry, and biochemistry. as a result of this (h2o)n systems have received a great significant of attention, both experimental and theoretical. all calculation of this study are carried out by gaussian 98 soft ware. geometry optimization for each cluster were be ...