title: Stereodynamic effects in the adsorption of propylene molecules on Ag(001).
abstract: We report on the experimental evidence of the role of rotational alignment of the gas-phase molecules in the interaction of propylene with Ag(001). Molecular alignment has been controlled by a velocity selection of the impinging molecules, flying in a supersonic seeded molecular beam. The experimental findings indicate that at low surface coverage the sticking probability is independent of molecular alignment, while when coverage exceeds few percent of a monolayer, molecules impinging rotating parallel to the surface (helicopter-like configuration) achieve a higher chance to be trapped than those which impinge rotating perpendicularly (cartwheels). The sudden appearance of a large stereodynamic effect suggests that the adsorption proceeds via a mobile precursor state and is tentatively correlated with a change in the configuration of the added propylene molecules, which adsorb tilted rather than flat at the surface.
authors.affiliation: Dipartimento di Fisica, Universita Genova, Via Dodecaneso 33, Genova, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Gerbi
authors.forename: L
authors.initials: L
authors.lastname: Vattuone
authors.forename: M
authors.initials: M
authors.lastname: Rocca
authors.forename: F
authors.initials: F
authors.lastname: Pirani
authors.forename: U
authors.initials: U
authors.lastname: Valbusa
authors.forename: D
authors.initials: D
authors.lastname: Cappelletti
authors.forename: F
authors.initials: F
authors.lastname: Vecchiocattivi