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Role of excitons in electron- and photon-stimulated desorption of neutrals from alkali halides.

Research paper by A A Alexandrov, M M Piacentini, N N Zema, A C AC Felici, T M TM Orlando

Indexed on: 15 Feb '01Published on: 15 Feb '01Published in: Physical review letters



Abstract

Low-energy (5-15 eV) electron- and photon-stimulated desorption of KI(100) yields I2P3/2 and 2P1/2 with hyperthermal (0.3 eV) and thermal velocity components. The desorption threshold for both components is 5.3 eV and is correlated with the gamma3/2-exciton long-wavelength edge. Exciton decay at the surface directly produces I2P3/2 and 2P1/2 with hyperthermal velocity and is in competition with self-trapping. Spin memory of the gamma-exciton hole-component is also evident in the hyperthermal channel. An exciton mediated desorption mechanism is presented which is general in alkali halides.