A density functional theory study on the reactions of Y atom and Y⁺ cation with carbonyl sulfide

Abstract

ABSTRACT:The mechanism of the title reactions have been studied by using the DFT (B3LYP/ECP/6-311ϩG*) level of theory. Both ground and excited state potential energy surfaces are discussed. It is found the reaction mechanism is insertion mechanism both along the COS and COO bond activation branches, but the COS bond activation is much more favorable in energy than the COO bond activation. The reaction of Y atom with SCO was shown to occur preferentially on the ground state (doublet) PES throughout the reaction process, and the experimentally observed species, have been explained according to the mechanism revealed in this work. Different from that of Y ϩ SCO system, the reaction between Y ϩ cation and SCO involves potential energy curve-crossing which dramatically affects reaction mechanism. Due to the intersystem crossing existing in the reaction process of Y ϩ with SCO, the intermediates SY ϩ ( 2 CO) and OY ϩ ( 2 CS) may not form. All our theoretical results not only support the existing conclusions inferred from early experiment, but also complement the pathway and mechanism for this reaction.