A test set of 21 radical addition and 28 hydrogen abstraction reactions has been studied at the W1, G4, G3X, G3X(MP2), and G3X(MP2)-RAD levels of theory with a view to establishing whether the recently introduced G4 theory offers improved performance over the G3 methods. All methods tested approximated the benchmark W1 values to within a mean absolute deviation (MAD) of 4 kJ mol(-1) or less, al...

Adsorption of water onto metal oxide surfaces is a long-standing problem motivated by relevance to many promising technological applications. In this work, we compute the adsorption energy of water on SrTiO3 using periodic Møller-Plesset second-order perturbation theory (MP2). We compare our MP2 results to density functional and hybrid density functional theory calculations with and without the...

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...

A set of 148 molecules having well-established enthalpies of formation at 298 K is presented. This set, referred to as the G2 neutral test set, includes the 55 molecules whose atomization energies were used to test Gaussian-2 ~G2! theory @J. Chem. Phys. 94, 7221 ~1991!# and 93 new molecules. The G2 test set includes 29 radicals, 35 nonhydrogen systems, 22 hydrocarbons, 47 substituted hydrocarbo...

The complexes formed between three molecules where the diboryl units (HBH2BH) replace C2H2 moiety in benzene (B6H12, C2B4H10, and C4B2H8) 10 anions (H−, F−, Cl−, Br−, OH−, CCH−, CH3−, CN−, N3−, CNO−) have been studied using MP2 computational methods with complete basis set (CBS) extrapolation scheme. stability of for a given anion increases number diborane molecules, these energy values are cor...

the character of the intermolecular interactions in cl2-hx (x =f, cl and br) complexes has been investigated by means of the second-order möller–plesset perturbation theory (mp2) and the density functional theory (dft) calculations. the results show that there are two types of lowest interaction potential equilibrium structures in the interactions between cl2 and hx: x∙∙∙cl type geometry and hy...

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 show how an embedded many-body expansion (EMBE) can be used to calculate accurate ab initio energies of water clusters and ice structures using wavefunction-based methods. We use the EMBE described recently by Bygrave et al. [J. Chem. Phys. 137, 164102 (2012)], in which the terms in the expansion are obtained from calculations on monomers, dimers, etc., acted on by an approximate representat...

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 ...