Static-Mode Laser-Fluorescence Spectroscopy: A New Technique for Studying Excitation Mechanisms in Particle-Surface Collisions

摘要

The recent development of static mode laser fluorescence spectroscopy provides a new technique for measuring the hitherto inaccessible distributions among low lying excited electronic energy levels at well defined surface oxygen coverages. Because of the sensitivity and selectivity of the LFS method, it is now possible to probe the effects on excitation coefficients of oxygen coverages at monolayer levels using simultaneous Auger measurements which in turn can be correlated with specific adsorbate structures based on LEED, ISS and ELS studies. The results of such measurements are discussed and evaluated in the light of current theoretical models. Excited state distributions determined by LFS on low lying manifolds are now available on a variety of systems (e.g., Ti, Fe, Zr, U) and point to much lower temperatures, 0.01-0.1 eV, for the low lying states compared to 0.5-1 eV for the SCANIIR and excited ion state levels. Recent work on the effect of monolayer oxygen coverages on Ti metal using static mode LFS is rviewed and detailed correlations made between excited state populations and specific oxygen bonding states to the metal surface. (ERA citation 08:024521)