Thermal spike model for heavy ion induced desorption
We have seen that the surface thermal spike model of HIID/PDMS can reproduce the linear dependence of ion yield versus LET found by Hakansson et al.  at high LET. We have also shown that postdesorption collisions can significantly effect the angular and kinetic energy distributions of the desorbing molecular ions. We might also speculate that the postdesorption collisions could be an important ionization mechanism and could lead to cooling of internal modes of the molecular ions, thus leading to enhanced molecular ions yields compared to those which would be obtained without postdesorption collisions.
At present we are extending these studies by developing a dynamical model for the desorption process so that we can study the competition between energy transfer and desorption in larger molecular systems. In addition we are refining the Monte Carlo simulations by performing two dimensional simulations which consider the dependence of the velocity and density distributions in both the direction normal to the surface and in radial direction normal to the primary ion track.
KeywordsLinear Energy Transfer Vibrational Excitation Transition State Theory Nuclear Motion Kinetic Energy Distribution
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