The binding energy and geometrical structure of all the possible dimeric systems of isothiocyanic acid (HNCS) with ozone have been investigated in the gas phase, theoretically. Six minima located on the singlet potential energy surface of the HNCS–ozone system at the MP2 level with binding energies (corrected with ZPE and BSSE) in the range 492.29–531.40 kcal/mol. All intermolecular interaction...

We have performed reference quantum-chemical calculations for about 130 structures of adenine dimers in stacked conformations, with special attention given to dimers that are either vertically compressed (parallel structures) or contain close interatomic contacts (non-parallel structures). Such geometries are sampled during thermal fluctuations of nucleic acids and contribute to the local confo...

When calculating the spin multiplicity at either second-order Møller-Plesset (MP2) or iterative approximate coupled-cluster singles and doubles (CC2) levels of theory using same strategy for calculation expectation value as in regular CC together with usual definitions MP2 CC2 density matrices, artificial contamination occurs closed-shell molecules. Non-intuitively, open-shell systems, results ...

The ab initio scalar ZORA approach, which was previously tested within the context of numerical and basis set SCF calculations, is generalized to include electron correlation. The technical details of the method are investigated in calculations on the systems Ne2, Ar2, Kr2 and Xe2. For the weakly bonded rare gas dimers we calculated the bond lengths and well depths using the non-relativistic ZO...

The HF/3s2pld and MP213s2pld structures, energies and vibrational frequencies were calculated for ten N8 isomers, corresponding to ten analogous CH structures. Comparative calculations using density functional theory (DFT), with a cc-pVTZ basis set, were also performed. All ten structures were found to be local minima on the energy hypersurface at the Hartree-Fock (HF) level, whereas at the sec...

Ab initio MP2/aug’-cc-pVTZ calculations have been carried out to determine the structures and binding energies of complexes BeF2, BeF3–1, BeF4–2 with n H2O molecules, n = 1–6. For each ...

the methamphetamine has been studied theoretically at the mp2 [1]/6-31g[2] level in gas phase.methamphetamine has been investigated via nmr, frequencies calculation and nbo analysis. thestructure of methamphetamine was designed primarily using of chem. bio draw and it geometry hasbeen optimized at the mp2/6-31g computational level. the present work consists the study of themethamphetamine repor...

Predictions of the BLYP density functional are compared with wavefunction-based calculations for several structural and Ž . q dynamical properties of H O H . We focus attention on properties important for proton transfer in this cluster. Good 2 3 Ž . agreement between density functional theory DFT calculations and all-electron MP2 results is found for energies, structures, and vibrational prope...