The yields of electron emission from a CsI surface bombarded with very heavy molecular ions have been measured by coincidence counting in time-of-flight mass spectrometry. These ions were produced by the matrix-assisted laser desorption/ionization technique. The masses ranged from 700 to 66 000 Da with velocities V between 5 × 10 3 and 7 × 10 4 ms For a few years, the interaction of heavy clusters and molecules with solids has been the subject of welldeveloped research. In these investigations the projectiles have had energies from a few eV/atom to a few MeV/atom. Over this large domain of velocities, the projectiles deposit a large amount of energy near the surface of the target. For masses in the range of 10 000 u to 100 000 u, energies of 10 keV to 2 MeV are deposited in a small volume. The transfer of very high densities of transitory and out-of-equilibrium energy into the solid leads to important modifications of the material and/or to the formation of craters independent of the energy range, the mass of the projectiles and the nature of the bombarded surface.1-5 Crater formation is accompanied by a very high sputter yield, as was first observed by Andersen and Bay. 6 The other de-excitation channels, such as electron and ion emission, have also been studied. The ion emission yield exhibits a non-linear increase as a function of the number of constituents or the mass of the projectile over the velocity range studied.7-10 For electron emission, results are scarce. Fundamentally, the electron emission induced by ions is connected to the ion/electron interaction in the medium. The electron emission processes are not simple, and the experimental results show both linear and non-linear relationships of the electron emission yield as a function of the velocity of the projectiles. 11-13

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Some cascades of Auger and radiative transitions following inner-shell ionisation have been simulated using the Monte Carlo method and taking the energy of transitions from the relativistic Hartree-Fock-Pauli approximation. It has been found that the configurations, in which all Auger transitions are energy forbidden, play an essential role in the cascade development. This energy prohibition and a more correct estimation of several-electron shake-off improves the agreement of the theory with the experiments on ion charge distribution. The calculated Auger electron and x-ray spectra are presented.

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