It is well established that reaction cycles involving inorganic halogens contribute to the depletion of ozone in atmosphere. Here, kinetics O3 with halogen atoms (Cl, Br, and I) were investigated between 180 400 K, expanding temperature range relative prior studies. Canonical variational transition state theory including small curvature tunneling correction (CVT/SCT) considered, following const...

The optimized geometry and energy for [K(H2O)n=1-8] clusters have been studied using different basis sets and different methods (HF, MP2(FULL), BLYP and B3LYP). Moreover, two analytical potentials have been developed for potassium in water based on MP2(FULL) and B3LYP computations using the 6311g* for potassium and the aug-cc-pVTZ(H2O) basis set for water. Two molecular dynamics simulations hav...

A new database of nucleic acid base trimers has been developed that includes 141 geometries and stabilization energies obtained at the RI-MP2 level of theory with the TZVPP basis set. Compared to previously compiled biologically oriented databases, this new construct includes considerably more complicated structures; the various intermolecular interactions in the trimers are quite heterogeneous...

The performance of a variety of DFT functionals (BLYP, PBE, B3LYP, B3P86, KMLYP, B1B95, MPWPW91, MPW1B95, BB1K, MPW1K, MPWB1K, and BMK), together with the ab initio methods RHF, RMP2, and G3(MP2)-RAD, and with ONIOM methods based on combinations of these procedures, is examined for calculating the enthalpies of a range of radical reactions. The systems studied include the bond dissociation ener...

We propose to construct electron correlation methods that are scalable in both molecule size and aggregated parallel computational power, in the sense that the total elapsed time of a calculation becomes nearly independent of the molecular size when the number of processors grows linearly with the molecular size. This is shown to be possible by exploiting a combination of local approximations a...

Aromatic amino acid residues are often present in carbohydrate-binding sites of proteins. These binding sites are characterized by a placement of a carbohydrate moiety in a stacking orientation to an aromatic ring. This arrangement is an example of CH/pi interactions. Ab initio interaction energies for 20 carbohydrate-aromatic complexes taken from 6 selected ultra-high resolution X-ray structur...