A computational study on the reaction of yttrium with ketene

The reaction of yttrium (2D) with ketene (H2CCO) examined recently in crossed molecular beam experiments has been studied at B3LYP and CCSD (T) level. After the formations of different π-complexes with Y binding to CCO, CC and CO sites, respectively, several reaction channels are open. Two possible H-elimination pathways have been identified and they were found to correlate with singlet ground state and triplet excited state product, 1YCHCO and 3YCHCO, respectively. Three possible H2-elimination pathways have been identified, and the calculation results indicate that the two concerted pathways can be competing processes at low energy, while the step-wise mechanism needs higher collision energy. The experimentally observed products YCCO were found to exist in two different forms (cyclic and linear). The calculated barrier of Y insertion into CC bond leading to the dominant product YCH2 at low collision energy in CMB study is only 2 kcal/mol and the potential energy surface of this reaction is flat. In addition, the insertion of Y into CO bond was also identified, but this reaction is correlated to the product (vinylidene H2CC) with excited state, agreeing with the fact that the formation of YO+H2CC was not observed in experiment.