COULOMB EXPLOSION OF H-2(+) IN SURFACE SCATTERING

We consider Coulomb explosion of H-2(+) scattered from W(100) at grazi ng angles and at energies of 400 keV to 1.6 MeV. Classical trajectorie s simulations are performed, where elastic and inelastic forces determ ine the fragment distributions. As physical input we take repulsive el astic interactions, electronic stopping, image force, wake force, init ial molecule vibration and rotation, and electronic straggling. Our re sults compare well to measurements with regard to the asymmetry of two peaks in the energy spectrum. A more precise explanation for the 'ali gnment effect' previously found in experiments is given in terms of re -encounter collisions. A rough estimate of the ionization distance fro m the surface where Coulomb explosion sets in can be deduced from our results. (C) 1998 Published by Elsevier Science B.V. All rights reserv ed.