Dynamics of the defect-mediated desorption of alkali halide surfaces

Abstract

Dynamic processes leading to desorption of Rb and I atoms from the RbI (100) surface co-irradiated with 1 keV electrons and visible light (with a wavelength corresponding to the F-center absorption band) have been studied by means of mass-selected time-of-flight (TOF) spectroscopy. Depending on the sample temperature, substantial enhancement of the desorption yield, as well as pronounced changes in the TOF spectra of the emitted atoms have been found. The TOF spectra of halogen atoms consist of two components: thermal (which can be fitted with Maxwellian distribution) and non-thermal one. The non-thermal peak is temperature-independent. There is no non-thermal component for alkali atoms. The comparison of TOF spectra for I atoms emitted from electron bombarded sample with and without simultaneous light irradiation indicates that the yield increase is caused by thermally desorbed atoms, while the non-thermal peak remains unchanged. Presented results confirm well the predictions of the theoretical model of desorption proposed earlier, known as the defect-mediated (F and H center) desorption of alkali halides.

Highly charged ion induced nanostructures at surfaces by strong electronic excitations

“…As a consequence, less anisotropic erosion is expected for lighter primary ions. Indeed, the threshold for the development of anisotropic ripple structures on KBr surfaces irradiated with He + projectile is shifted to a much larger fluence as compared to the case of irradiation with heavier Ar + ions [68,70].…”

Computer Simulations of the Band Structure and Density of States of the Linear Chains of NaCl Ions

“…They have many interesting physical properties such as high melting point, strong miscibility, and large band gaps. Due to the fact that in these materials the effective exciton mechanism [1]- [10] of the formation of radiation defects is implemented, they are widely used as radiation detectors, such as scintillators [11]- [15] and a storage phosphors for image plate detectors and optically stimulated dosimeters [16]- [20]. Moreover, alkali halides are used as infrared (IR) optical windows and optoelectronic devices [21], [22].…”

Slow highly charged ion induced nanopit formation on the KCl(001) surface

“…From electron irradiation of alkali halide surfaces a layer-by-layer desorption process was identified [7,[28][29][30][31]. Impacting electrons excite bound electrons in the lattice forming an exciton which gets rapidly self-trapped due to the charge background of the ionic crystal.…”