Auger-induced valence processes in alkali halides following alkali core-hole creation

Journal Article · Wed Mar 15 04:00:00 EST 1989 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.39.5407· OSTI ID:6418058

Green, T A; Riley, M E; Richards, P M; Loubriel, G M; Jennison, D R; Williams, R T

Ab initio calculated values are presented for the interatomic Auger and radiative decay rates for initial (2p)/sup 2/ and 2p hole states of the Na ion in NaF. A comparison of the rates shows that these hole states decay overwhelmingly by the nonradiative Auger process. The knowledge of the rates makes possible a clarification of the mechanism of photon-stimulated positive-ion desorption presented by Parks et al. (Phys. Rev. B 28, 4793 (1983)). Following the creation of a Na(1s) hole in NaF, the ensuing Auger cascade results in the creation of four to six valence holes, or one F/sup +/ ion and two to four valence holes, on the neighboring negative fluorine ions within an elapsed time of a few times 10/sup -14/ s. The majority of the valence holes are produced as hot holes, and are likely to diffuse several tens to hundreds of angstroms in times of the order of picoseconds before self-trapping to form V/sub K/ centers. The fast diffusion of these holes greatly reduces their chance of participating in ion desorption processes. The possibility that a fraction of the holes self-trap immediately and assist in the desorption of positive ions is considered. It is found that positive-ion desorption can occur if enough holes self-trap immediately. However, the required configurations are so special that they may occur with too small a probability to account for the observed positive-ion current. The fast hole diffusion also makes it unlikely that the V/sub K/ centers from the cascade will exhibit the clustering effects which would have been expected had the holes self-trapped in place.

• Research Organization: Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185-5800
• OSTI ID: 6418058
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 39:8; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ALKALI METAL COMPOUNDS
AUGER EFFECT
BAND THEORY
CHARGED PARTICLES
COLOR CENTERS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DESORPTION
DIFFUSION
ELECTRON-HOLE COUPLING
ENERGY LEVELS
FLUORIDES
FLUORINE COMPOUNDS
FLUORINE IONS
HALIDES
HALOGEN COMPOUNDS
HOLES
INNER-SHELL IONIZATION
IONIZATION
IONS
P STATES
POINT DEFECTS
RADIATIVE DECAY
SODIUM COMPOUNDS
SODIUM FLUORIDES
TRAPPING
V CENTERS
VACANCIES
VALENCE