Characterization and Atmospheric Implication of Hydrotrioxy Radical-Water-Methylamine-Formic Acid-Sulphuric Acid Complexes.

New particle formation is an important source of atmospheric aerosols, but the nucleation phenomena is still poorly understood. Here the formation of bimolecular complexes of HOOO• radical with H2O, CH3NH2, HCOOH and H2SO4 has been investigated by quantum chemical methods. The stabilising effect of methylamine is found to be close to that of sulphuric acid, both complexes are formed spontaneously at studied atmospheric conditions.

Hydrogen bonding in the hydroxysulfinyl radical-formic acid-water system: A theoretical study.

Quantum chemical methods have been employed to evaluate the possible configurations of the 1:1 and 1:2 HOSO-formic acid complexes and 1:1:1 HOSO-formic acid-water complexes. The first type of complex involves two H bonds, while the other two types comprise three H bonds in a ring. The complexes are relatively stable, with CBS-QB3 computed binding energies of 14.

H-Bonded CH3SO/H2SO4/H2O Complexes: A Quantum Chemical Study.

The structural, electronic, and spectroscopic properties of complexes of the methyl sulfinyl radical, sulphuric acid and water molecules have been studied by density functional theory and ab initio methods. The hydrogen bond interactions between the CH(3)SO radical, H(2)SO(4) and H(2)O molecules have been characterised. The calculations predict relatively large binding energies for the complexes of 12.

Structure, stability, and spectroscopic properties of H-bonded complexes of HOSO and CH3SO with H2O.

Quantum chemical calculations have been carried out to investigate the structure and stability of 1:1 and 1:2 HOSO-water and CH3SO-water complexes. All of the geometries have been optimized at the DFT and at the CCSD levels of theory using 6-311++G(2df,2pd) and aug-cc-pVDZ basis sets, respectively. The energetics of the hydrogen-bonded complexes are reported at G4 and CBS-QB3 levels of theory.

Triazole, benzotriazole, and naphthotriazole as copper corrosion inhibitors: I. Molecular electronic and adsorption properties.

The gas-phase adsorption of 1,2,3-triazole, benzotriazole, and naphthotriazole-considered as corrosion inhibitors-on copper surfaces was studied and characterized using density functional theory (DFT) calculations. We find that the molecule-surface bond strength increases with increasing molecular size, thus following the sequence: triazole View Article and Find Full Text PDF

Atmospheric reaction of the HOSO radical with NO2: a theoretical study.

The gas-phase reaction between HOSO and NO(2) was examined using density functional theory. Geometry optimizations and frequency computations were performed at the B3LYP/6-311++G(2df,2pd) level of theory for all minimum species and transition states. The ground-state potential energy surface, including activation energies and enthalpies, were calculated using the ab initio CBS-QB3 composite method.

Theoretical study on the mechanism of the reaction of CF(3)S with NO(2).

The singlet potential energy surface for the CF3S + NO2 reaction has been theoretically investigated using the B3LYP/6-311+G(3df) level of theory. The geometries, vibrational frequencies, and zero-point energies of all stationary points involved in the title reaction have been examined. More accurate energies of stationary points were obtained using ab initio G3//B3LYP and CBS-QB3 composite methods.

Effect of halogenation on the mechanism of the atmospheric reactions between methylperoxy radicals and NO. A computational study.

The mechanism of the reactions between the halogenated methylperoxy radicals, CHX(2)O(2) (X = F, Cl), and NO is investigated by using ab initio and density functional quantum mechanical methods. Comparison is made with the mechanism of the CH(3)O(2) + NO reaction. The most important energy minima in the potential energy surface are found to be the two conformers of the halogenated methyl peroxynitrite association adducts, CHX(2)OONOcp and CHX(2)OONOtp, and the halogenated methyl nitrates, CHX(2)ONO(2).

Electronic spectrum and photodissociation of ClONO in comparison to BrONO.

A theoretical study of the low-lying singlet and triplet states of ClONO is presented. Calculations of excitation energies and oscillator strengths are reported using multireference configuration interaction, MRD-CI, methods with the cc-pVDZ + sp basis set. The calculations predict the dominant transition, 4(1)A' <-- 1(1)A', at 5.

Quantum mechanical investigation of the atmospheric reaction CH3O2 + NO.

The important stationary points on the potential energy surface of the reaction CH(3)O(2) + NO have been investigated using ab initio and density functional theory techniques. The optimizations were carried out at the B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) levels of theory while the energetics have been refined using the G2MP2, G3//B3LYP, and CCSD(T) methodologies. The calculations allow the proper characterization of the transition state barriers that determine the fate of the nascent association conformeric minima of methyl peroxynitrite.

Quantum mechanical study of the potential energy surface of the ClO + NO2 reaction.

In the study of the reaction pathways of the ClO + NO2 reaction including reliable structures of the reactants, products, intermediates, and transition states as well as energies the MP2/6-311G(d), B3LYP/6-311G(d), and G2(MP2) methods have been employed. Chlorine nitrate, ClONO2, is formed by N-O association without an entrance barrier and is stabilized by 29.8 kcal mol(-1).

Enthalpy of the gas-phase CO2 + Mg reaction from ab initio total energies.

Various highly accurate ab initio composite methods of Gaussian-n (G1, G2, G3), their variations (G2(MP2), G3(MP2), G3//B3LYP, G3(MP2)//B3LYP), and complete basis set (CBS-Q, CBS-Q//B3LYP) series of models were applied to compute reaction enthalpies of the ground-state reaction of CO2 with Mg. All model chemistries predict highly endothermic reactions, with DeltaH(298) = 63.6-69.

Transition state structure and energetics of the N(2)O + X (X = Cl,Br) reactions.

The structural and vibrational properties of the transition state of the N(2)O + X (X = Cl,Br) reactions have been characterized by ab initio methods using density functional theory. We have employed Becke's hybrid functional (B3LYP), and transition state optimizations were performed with 6-31G(d), 6-311G(2d,2p), 6-311+G(3d,2p), and 6-311+G(3df,2p) basis sets. For the chlorine atom reaction the coupled-cluster method (CCSD(T)) with 6-31G(d) basis set was also used.