Time of flight spectra and chaotic dynamics in predesorption of physisorbed molecules

The phase space properties of 2D classical Hamiltonian nonlinearly coupled models are used to work out the asymptotic momentum distributions and the time of flight spectra for elastic predesorption of CO and CH3F molecules physisorbed on NaCl(100). Such spectra are shown to display several peaks which are related to the presence of dynamical barriers (bottlenecks) in the phase space induced by the chaotic Hamiltonian dynamics characteristic of these systems reflecting the structure of the multidimensional physisorption potential.