title: Kinetics and energetics of oligomer desorption from surfaces.
abstract: The dynamics of oligomer desorption from surfaces has been studied by measuring the desorption kinetics of a set of straight chain alkanes [ H(CH2)(n)H, with n = 5 to 60] from the surface of single crystalline graphite. Desorption is observed to be a first-order process and the preexponent of the desorption rate constant has a value nu = 10(19.6+/-0.5) sec(-1) and is independent of the oligomer chain length. More interestingly, we find that the barrier to desorption has a nonlinear dependence on chain length and takes the form DeltaE(double dagger)(des) = A+Bn(alpha), with the exponent alpha = 0.50+/-0.01.
authors.affiliation: Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: K R
authors.initials: KR
authors.lastname: Paserba
authors.forename: A J
authors.initials: AJ
authors.lastname: Gellman