LOW-ENERGY-ELECTRON STIMULATED DESORPTION OF METASTABLE PARTICLES FROM CONDENSED N-2 AND CO

The impact of low-energy electrons (7-19 eV, Delta E=60 meV) is found to induce desorption of metastable particles (N-2 and CO*) from conde nsed multilayer N-2 and CO films. For N-2 films, the yield function of the metastable-particle signal, which shows two regions (below and ab ove 11 eV) of large intensity difference, is assigned to excitations t o the valence state B3IIg and to the Rydberg state E(3) Sigma(g)(+), r espectively. Desorption of N-2 above 11 eV is believed to be due to t he repulsive interaction between the excited molecules and the solid s urface. The desorp,tion yield of CO, which is much weaker than that f or ,,is discussed in terms of vibrational energy transfer from the vib rational excited a'(3) Sigma(+) state.