ELECTRON-STIMULATED DESORPTION OF KR(2+) FROM THE SURFACE OF SOLID KR

We have observed that electronic excitations of condensed Kr by low-en ergy electron impact resulted in the desorption of Kr+, Kr2+, Kr3+, an d Kr2+ from the surface of solid Kr. The measurement of the impact ene rgy dependence of Kr2+ desorption yields showed a threshold at an impa ct energy of 83 eV and the yield increased drastically at an impact en ergy between 100 and 120 eV. By referring to the excitation energy in the gas phase, these energies can be attributed to 4p-3 (triple), 3d-1 (inner shell), 3d(-1)4p-1nl (shake up), and 3d(-1)4p-1 (shake off) Kr atom ionizations. The results suggest that these Kr atom ionization p rocesses are the primary excitation leading to the desorption of Kr2from the surface. The onsets of the desorption at the shake ionization energies were significant. We concluded that the interatomic Auger tr ansition between a primarily excited atom and a neighbor neutral which follows 3d shake ionization of Kr plays an important role in the deso rption process of Kr2+.