Research into the mechanism of the desorption induced by electronic transitions (DIET) at the surface of rare gas solids

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We have investigated the desorption at the surface of rare ges solids innduced by electron and photon irradiation on it. The results achieved in this research project are summarized below.1. We have ascertained the validity of the cavity-ejection mechanism, which has been proposed for the desorption of metastables initiated by a surface exciton, by the detailed measurement of the kinetic energy distribution and the angular distribution of desorbed species. The absolute yield of desorption was also determined. This is regarded as a first step to give a quantitative picture of the desorption process.2. We have revealed that the desorption and the deexcitation process after the excitation of 2p^53p-type surface exciton, which is allowed only at surface, has a complex aspect in connection with its fine structure.3. In the experimental study on the alloy of rare gas solids, we have found a characteristic feature, selectivity of desorbed species for example, which was likely related to the excitation energy exchange between hetero-species and the diffusion of an exciton in alloyed matrix.4. We have revealed that a small amount of hydrogen physisorbed on the surface of rare gas solids causes a significant effect on the desorption process.5. Through the measurement of the excitation spectrum, the luminescence, and the kinetic energy of desorbed species with a high resolution apparatus, we got the clue which may reveal the detail of the elementary process, such as, the cascade of deexcitation, the diffusion process, so on.