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 (...

p53 is one of the gene that has important role in human cell cycle and in the human cancers too.models of codon substitution make it possible to separate mutational biases in the dna fromselective constraints on the protein, and offer a great advantage over amino acid models forunderstanding the evolutionary process of proteins and protein-coding dna sequences. in thiswork, we investigated abou...

topological indices are one of the oldest and most widely used descriptors in quantitative structureproperties relationvhips (qspr). amongst the topological indices used a,s descriptors in qspic., the wienerindex is by far the most popular index. as it has been shown that the wiener index has a strong correlationwith the chemical propenies of the compound.in this study, the relationship between...

a computational study of the electronic structure and stability of complexes formed between zeolite y and boric acid was carried out at the hf and b3lyp levels using 6-31g* basis set. five structures located as local minimum in pes of complex (structures d, e, f, g, and h). the most stable structure is formed due to hydrogen bonding between two hydroxyl of boric acid and both oxygen of ...

A systematic method for approximating the ab initio electronic energy of molecules from the energies of molecular fragments has been adapted to estimate the total electronic energy of crystal lattices. The fragmentation method can be employed with any ab initio electronic structure method and allows optimization of the crystal structure based on ab initio gradients. The method is demonstrated o...

Previously we searched for the ab initio global minima of several SixHy clusters by a genetic algorithm in which we used the AM1 semiempirical method to facilitate a rapid energy calculation for the many different cluster geometries explored. However, we found that the AM1 energy ranking significantly differs from the ab initio energy ranking. To better guarantee locating the ab initio global m...

vinblastine is an important anticancer agent known to diminish microtubule assembly. ab initio calculations are applied to examine the structural properties and different energies of vinblastine-tubulin complex in different dielectric constants and temperatures. the aims of this work are discovery the best optimized structure and thermodynamic properties of vinblastine-tubulin complex and compa...

A tight-binding total-energy (TBTE) method has been developed to interpolate between firstprinciples results describing the dissociation of molecules at surfaces. The TBTE scheme requires only a relatively small number of ab initio energies as input and gives a reliable global representation of the ab initio potential energy surface to within 0.1 eV accuracy compared to the ab initio results. T...

The ground-state geometry of the NiC3 and NiC4 clusters is investigated using accurate ab initio methods and compared with predictions using the tight-binding molecular-dynamics ~TBMD! method as well as the density functional theory ~DFT! based SIESTA method. The ab initio methods predict the ground-state geometry of the NiC3 cluster to have a rhomboidal geometry, in agreement with the TBMD met...