title: Sticking and desorption of hydrogen on graphite: a comparative study of different models.
abstract: We study the physisorption of atomic hydrogen on graphitic surfaces with four different quantum mechanical methods: perturbation and effective Hamiltonian theories, close coupling wavepacket, and reduced density matrix propagation methods. Corrugation is included in the modeling of the surface. Sticking is a fast process which is well described by all methods. Sticking probabilities are of the order of a few percent in the collision energy range 0-25 meV, but are enhanced for collision energies close to those of diffraction resonances. Sticking also increases with surface temperature. Desorption is a slow process which involves multiphonon processes. We show, however, how to correct the close coupling wavepacket method to account for such phenomena and obtain correct time constants for initial state decay. Desorption time constants are in the range of 20-50 ps for a surface temperature of 300 K.
authors.affiliation: Laboratoire Collisions Agrégats Réactivité, IRSAMC, Université de Toulouse, UPS, F-31062 Toulouse, France. bruno.lepetit@irsamc.ups-tlse.fr
authors.forename: Bruno
authors.initials: B
authors.lastname: Lepetit
authors.forename: Didier
authors.initials: D
authors.lastname: Lemoine
authors.forename: Zuleika
authors.initials: Z
authors.lastname: Medina
authors.forename: Bret
authors.initials: B
authors.lastname: Jackson