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Abstract: Ab initio calculations of the two title reactions have been made to compare reactivities of OCS and CS2 toward a nucleophile, . MP2/6-311++G(d, p) geometry optimizations on the singlet potential energy surface have demonstrated that respective channels start from key intermediates and have revealed that multistep paths give the most favorable products: (1) +OCS→H2NS− +CO; (2) +OCS→HS− +HNCO; (3) +OCS→NCS− +H2O; (4) +OCS→NCO− +H2S; (5) +CS2 →NCS− +H2S; (6) +CS2 →HS− +HNCS. Furthermore, to get more reliable energetic data, single-point calculations are carried out at CCSD/6-311++G(d, p) level. The calculated result is consistent with the measured large rate constant in experiment. A comparison of reaction mechanisms is offered between +OCS and +CS2. [ABSTRACT FROM AUTHOR]

Abstract: The entire reaction mechanism for the gas phase CO–CO2 conversion by FeO+ is discussed by means of the density functional theory and the intrinsic reaction coordinate approach. The calculated results have strongly indicated that the reaction of is a spin-forbidden reaction between the quartet and the sextet potential energy surfaces (PESs). There is a crossing point between the quartet and the sextet potential energy surfaces which may play a significant role in this reaction, by which the activation energy can be decreased from −15.1 to −56.4kJmol−1 at the reaction system. [Copyright &y& Elsevier]

Abstract: The reaction of Lu+ with CH3F, which was selected as a representative system of the activation of C–F bond in fluorohydrocarbons by late lanthanide cations, has been examined using density functional theory (DFT). The potential energy surfaces (PESs) of [Lu, C, H3, F]+ were explored in detail in both singlet and triplet electronic states. The electron-transfer reactivity of the reaction was analyzed using the two-state model, and a strongly avoided crossing behaviour on the transition state (TS) area was shown. The theoretical results can act as a guide to further theoretical and experimental researches. [Copyright &y& Elsevier]

Abstract: The reaction of La+ with CH3F, which was selected as a representative system of the activation of C–F bond in fluorohydrocarbons by bare lanthanide cations, has been examined using density functional theory (DFT) to explore more integrated reaction pathways and mechanisms on both singlet and triplet potential energy surfaces (PESs). A direct fluorine abstraction mechanism and an insertion–elimination mechanism were revealed, the related thermochemistry data involved in reaction of La++CH3F were determined. The crossing points (CPs) have been found by means of single-point computations as a function of the structural change along the intrinsic reaction coordinate (IRC) in this manuscript. The present results not only support the existing reaction conclusions inferred from early experimental data, but also complement the pathway and mechanism for this reaction, which can act as a guide for further experimental researches and theoretical investigations. [Copyright &y& Elsevier]

Abstract: The reactivity of X(3P) (X=Ge, Sn, Pb) with N2O(X1Σ) on both singlet and triplet potential energy surfaces have been investigated at the B3LYP level of theory. To accurately evaluate the activation barrier and reaction energy, the coupled cluster single point calculations using the B3LYP structures is performed. The calculated results are in good agreement with experimental observations. The (X=Ge, Sn, and Pb) reactions that Arthur Fontijn has been observed are spin-forbidden for formation of ground state products in the experiments. The present paper is discussed with the aid of the direct abstraction (DA) mechanism (also called the surface crossing model), a correlation argument based on separated fragments X+O+N2 can explain the inefficiency of the (X=Ge, Sn, and Pb) reactions at 298K by the need to switch electron configurations along low-energy adiabatic paths from ground-state reactants to energetically accessible product states. [Copyright &y& Elsevier]