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Abstract: The spin-forbidden reaction mechanism of Ir+ with CH3F to yield H2 or HF has been investigated using density functional theory (DFT) calculations. The overall H2 elimination reaction is calculated to be exothermic, by 36.3 kcal/mol. One pathway is found on three potential energy surfaces (PESs), whereas the HF-elimination reaction is exothermic by 32.8 kcal/mol, two reaction pathways are identified on the quintet and triplet surfaces, only one reaction pathway is identified on the singlet surface. The reaction mechanism can be explained by the simple donor–acceptor model. According to the revealed mechanism and the calculated potential energy surfaces, H2-elimination is energetically much more favorable than HF-elimination. These conclusions are consistent with the experimental observations. [Copyright &y& Elsevier]

Abstract: The gas-phase reactions of fluorocarbon compounds CH4– n F n (n =1–3) with Pt (3D, 1S) have been systematically explored via density functional theory (DFT) in order to investigate the mechanisms of these reactions. The results indicate that a reaction of CH3F with Pt (3D, 1S) experiences a rearrangement process to generate counterintuitive production (CH2F−PtH). CH2F2 and CHF3 activation by Pt (3D, 1S) yields high-oxidation-state complexes with carbon–metal double bonds. Moreover, the attack of platinum atoms on fluorine atoms in different fluorocarbon compounds involves intersystem crossing (ISC) between triplet and singlet state Potential Energy Surfaces (PESs). The crossing points (CPs) have been located by the intrinsic reaction coordinate (IRC) approach used by Yoshizawa et al. and corresponding minimum energy crossing points (MECPs) obtained by the mathematical algorithm proposed by Harvey et al. have also been used. Additionally, possible spin inversion processes are discussed using spin–orbit coupling (SOC) calculations. [ABSTRACT FROM AUTHOR]

Abstract: Activation of the N–N and N–O bonds by La+ in nitrous oxide has been examined systematically using both DFT and CCSD(T) methods. The calculated results indicate that the reaction of La+ (3F, 1D) with N2O (X 1∑) including several reaction pathways and numerous isomers, leads to oxidation, LaO+ (1∑, 3Δ)+N2 () or nitration, LaN+ (2∑+, 4∑+)+NO (X 1∏). The attack of the La+ on the O-end of N2O involves intersystem crossing (ISC) between singlet and triplet state potential-energy surfaces (PESs). Thus, possible spin-inversion process is discussed by means of spin–orbit coupling (SOC) calculations. The probability values of the single () and double () passes are estimated at MECP are approximately 6.682×10−2 and 0.125, respectively. The calculated results also revealed that the O-transfer reaction is energetically more favorable than the N-transfer reaction on the both spin state PESs. These results are in good agreement with experimental observations. [Copyright &y& Elsevier]

Abstract: Calculations based on density functional theory (DFT) have been carried out to investigate the multi-centered transition state (MCTS) reaction mechanisms associated with the gas-phase ion/molecule reaction of YNH+ with ethene. The potential energy surfaces (PESs), including both reaction pathways of hydrogen and ammonia elimination, have been explored and characterized. By contrast with ammonia elimination, dehydrogenation reaction channel is energetically favorable, which is in good agreement with the experimental observation. Moreover, the dominating product (YC2H3N+) can further react with ethene and the corresponding reaction mechanism which proceeds in a two-step manner and leads to the six-membered metallacyclic structure YC4H5N+, has also been investigated. [Copyright &y& Elsevier]