Role of excitons in electron- and photon-stimulated desorption of neutrals from alkali halides.
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.
Alexandrov
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A
School of Chemistry and Biochemistry, Georgia Institute of technology, Atlanta 30332, USA.
Piacentini
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M
Zema
N
N
Felici
A C
AC
Orlando
T M
TM