UV-laser-induced desorption of NO from the pure and modified Cr2O3(0001) surfaces: spin effects in surface-state-induced desorption

摘要

Abstract: We shall report the UV-laser induced desorption of NO/Cr$- 2$/O$-3$/(0001) and the coadsorbate system NO/K/Cr$-2$/O$- 3$/(0001). Resonance enhanced multiphoton ionization was used for state selective detection of the desorbing NO after excitation with pulses of nanosecond duration and desorption laser energies between 3.5 eV and 6.4 eV. There are two adsorbate species of NO, a chemisorbed and a physisorbed species. We shall focus on data of the chemisorbed species. The main emphasis within this paper will be put on electron spin effects, particularly the preferential population of a fast translational desorption channel for the $+2$/$Pi$- 3/2$/ state observed specifically in connection with surface state induced processes at desorption energies of 5.0 eV. For those processes changes within the final state distributions of desorbing NO are fond when modifying the electronic surface structure via adsorption of small amounts of potassium.!25