Human beings use different methods to understand the world, religiously or scientifically, empirically or theoretically, synthetically or analytically. Quantum chemistry is one of the these methods. Starting from first principles of quantum mechanics, applying different mathematical and physical approximations, the behaviors of molecules are described. Before the discussion of the complex theor...

Here the ab-initio R-Matrix method has been used to carry out electron-molecule collision calculations on the the molecules of interstellar interest C3N, C2H & CN, and molecules found in industrial plasma applications SiBr, SiBr2 and NaI. These were carried out using the UK Molecular R-Matrix codes, along with the Quantemol expert system for running these codes. Calculations have also been carr...

We propose a generalized regression neural network (GRNN) approach based on grey relational analysis (GRA) and principal component analysis (PCA) (GP-GRNN) to improve the accuracy of density functional theory (DFT) calculation for homolysis bond dissociation energies (BDE) of Y-NO bond. As a demonstration, this combined quantum chemistry calculation with the GP-GRNN approach has been applied to...

The calculation of the internal partition function Qint, and the density of states N, is an important topic which has a vast range of applications. In fact, its accurate determination for a nonseparable potential is a long standing problem which goes back to the foundations of statistical mechanics. The density of states is required for the evaluation of reaction rate constants in transition st...

Abstract Based on first-principles calculation, the adsorption of sulfur-based gas molecules (H 2 S, SO , 3 ) various metal-decorated phosphorenes is researched systematically. Eleven metals (Li, Na, K, Rb, Cs, Ca, Sr, Ba, Ni, La, Tl) which can avoid formation clusters phosphorene are considered. Noticeably, all metal decorations enhance strength to except for H S Tl-decorated phosphorene. Mean...

Molecular polar surface area (PSA), i.e., surface belonging to polar atoms, is a descriptor that was shown to correlate well with passive molecular transport through membranes and, therefore, allows prediction of transport properties of drugs. The calculation of PSA, however, is rather time-consuming because of the necessity to generate a reasonable 3D molecular geometry and the calculation of ...