Theoretical study on the reaction of the ground state 2Δ of TiS + with oxygen-transfer reagent: TiS ++H 2O→TiO ++H 2S in the gas phase

Abstract

The reaction mechanism of the ground state 2Δ of TiS + with oxygen-transfer reagent: TiS ++H 2O→TiO ++H 2S in the gas phase has been proposed and investigated by ab initio methods with 6-31G** basis set for non-metal atoms and the effective core potentials of Lanl2dz for Ti. The reaction is proceeding via two steps with seven stationary points (reactants, three intermediate complexes: ( a), ( b) and ( c) two transition states: TS1 and TS2, and products) on the reaction potential surface which involved two 1,3-hydrogen shift reactions from oxygen atom to sulfur atom via a four-center transition state. The activation barriers of the two transition states are −54.0 and −65.1 kcal/mol, respectively, at MP4 (SDTQ)/6-31G**//MP2/6-31G** level plus zero-point energy relative to the reactants, which indicates that cationic titanium sulfide is favorable to this type of reaction and the collision rate of the reactants forming the complex ( a) should be the main factor that determines the reaction rate.