Kinetics and energetics of oligomer desorption from surfaces |
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Authors: | Paserba K R Gellman A J |
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Institution: | Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA. |
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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. |
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