The three dimensional reference interaction site model integral equation theory (3D­RISM) combined with the ab initio molecular orbital method (3D­RISM­ SCF) is applied to a solvated macro molecular system. The solvation structure around a solute molecule is obtained from the 3D­RISM integral equation under the electrostatic potential of the solute molecule, calculated by the ab initio molecula...

It is now possible to calculate the ab initio quantum mechanics of very large biological molecules. Two things lead to this perspective, namely, (i) the advances of parallel supercomputers, and (ii) the discovery of a quantum formalism called quantum crystallography and the use of quantum kernels, a method that is well suited for parallel computation. The kernel energy method (KEM) carried to s...

The EBO model, originally proposed by Lennard-Jones and Hall, many years ago, is reexamined using localized orbitals (LMO) stemming from SCF ab initio calculations. It is found that only a· limited set of matrix elements is needed to build a Fock matrix F, (in localized basis) the diagonalization of which yields orbital energies of sufficient precision for use in the assignment of photoelectron...

An embedded-atom potential has been constructed for the intermetallic compound B2-NiAl by fitting to both experimental properties and ab initio data. The ab initio data have been generated in the form of energy-volume relations for a number of alternative structures of NiAl and Ni3Al, as well as for Ni and Al. The potential accurately reproduces the basic lattice properties of B2-NiAl, planar f...

Based on a first-principles approach, we present scaling rules for the band gaps of graphene nanoribbons (GNRs) as a function of their widths. The GNRs considered have either armchair or zigzag shaped edges on both sides with hydrogen passivation. Both varieties of ribbons are shown to have band gaps. This differs from the results of simple tight-binding calculations or solutions of the Dirac's...

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...