structural and magnetic properties of purine and pyrimidine nucleotides (cmp, ump, dtmp, amp, gmp, imp) were studied at different levels of ab initio molecular orbital theory. these calculations were performed at the hartree-fock level and density functional b3lyp methods. geometries were fully optimized by following cs symmetry restrictions. the standard 6-31g** basis set which includes polari...

to get a mole of a gas, it is necessary to calculate the intermolecular interaction. theseintermolecular interactions can be depicted by drawing the potential energy of a pair molecule inrelation to the distance. the intermolecular potential energy surface in the mixtures of ch4-h2cogases from ab initio calculations has been explored. in ab initio calculations the basis setsuperposition error (...

To get a mole of a gas, it is necessary to calculate the intermolecular interaction. Theseintermolecular interactions can be depicted by drawing the potential energy of a pair molecule inrelation to the distance. The intermolecular potential energy surface in the mixtures of CH4-H2COgases from ab initio calculations has been explored. In ab initio calculations the basis setsuperposition error (...

in this paper, the hydrogen bonding (hb) effects on the nmr chemical shifts of selected atoms in serineand serine-nh2o complexes (from one to ten water molecules) have been investigated with quantummechanical calculations of the 15n and 13c tensors. interaction with water molecules causes importantchanges in geometry and electronic structure of serine.for the compound studied, the most importan...

topological indices are the numerical value associated with chemical constitution purporting for correlation ofchemical structure with various physical properties, chemical reactivity or biological activity. graph theory is adelightful playground for the exploration of proof techniques in discrete mathematics and its results haveapplications in many areas of sciences. one of the useful indices ...

the interaction of magnesium hydrate at the phosphate oxygen atom of the pyrimidine nucleotides (cmp,ump,dtmp) were studied at the hartree-fock level theory. we used lanl2dz basis set for mg and 6-31g* basis set for atoms.the basis set superposition error (bsse) begins to converge for used method/basis set. the gauge-invariant atomic orbital (giao) method and the continuous-set-of-gauge-transfo...

This is a review of molecular modelling techniques which may be applied to studies of energetic materials. It focusses on ab initio ('first-principles') molecular orbital calculations, since these methods offer the greatest accuracy. Since ab initio calculations are very computer-intensive, approximate MO methods are also discussed, which offer reasonably accurate predictions with reduced calcu...