title: Interaction of H2 with Si(001)-(2 x 1): solution of the barrier puzzle.
abstract: The sticking probability of H2 on Si(001) is immeasurably small at room temperature, indicating the presence of a large energy barrier to adsorption. Surprisingly, the final state energy distributions of H2 molecules desorbing from Si(001) show no signs of having traversed such a barrier, in apparent contradiction with microscopic reversibility. Here we report experimental and theoretical evidence resolving this long-standing puzzle. Adsorption and desorption proceeding along two distinct, microscopically reversible pathways can explain all observations.
authors.affiliation: Department of Physics and Laboratory for Surface Modification, Rutgers University, Piscataway, New Jersey 08854, USA.
authors.forename: F M
authors.initials: FM
authors.lastname: Zimmermann
authors.forename: X
authors.initials: X
authors.lastname: Pan