Theoretical study on the reaction of the ground state 1Σ+ of LaS+ with oxygen-transfer reagent: LaS++H2O→LaO++H2S in the gas phase

The reaction mechanism of the ground state 1Σ+ of LaS+ with oxygen-transfer reagent: LaS++H2O→LaO++H2S in the gas phase has been proposed and investigated by ab initio methods. The reaction is proceeding via two 1,3-hydrogen-shift reactions from oxygen atom to sulfur atom (via TS1 and TS2). The activation energies of two steps are 20.8 and 29.5 kcal/mol, respectively, at MP4 (SDTQ)/6-31G∗∗//MP2/6-31G∗∗ level plus zero-point energy relative to their corresponding intermediate reactants. But TS1 locates higher in energy that TS2 by only 1.8 kcal/mol on the reaction path. The periodic trends of Sc, Y and La for this type of reaction were also discussed.