ANOMALOUS TEMPERATURE DEPENDENCE OF THE DESORPTION OF EXCITED SODIUM ATOMS INDUCED BY ION BOMBARDMENT OF SODIUM FLUORIDE CRYSTALS

摘要

We have observed anomalous temperature dependence in the ion-induced desorption of excited sodium atoms from sodium fluoride crystals. The fluorescence yield of the 3p-3d transition at 8195 Angstrom, and the 3p-4d transition at 5688 Angstrom increases steadily with temperature; however the yield of sodium doublet 3s-3p transition displays a pronounced maximum in the region of 160 degrees C. Fluorescence yields are also found to be nonlinear as a function of beam current at room temperature. To explain these experimental results, we propose a mechanism that involves electron transfer between the desorbing atoms and the bombarded surface. [References: 12]