Experimental studies of photon-surface interaction dynamics in the alkali halides

Conference · Wed Jan 01 04:00:00 EST 1986

DOI:https://doi.org/10.1117/12.936592· OSTI ID:5496576

Haglund, Jr, R F; Tolk, N H

We describe recent measurements which have provided, in unprecedented detail, insights into the electronic mechanisms through which energy carried into a material by photon irradiation is absorbed, localized and rechanneled to produce desorption, surface modification, erosion and damage. The specific object of these studies has been desorption induced by electronic transition in alkali halide crystals, with particular emphasis on the dynamics of changes in the surface and near-surface regions. In our experiments, the irradiating ultraviolet photons are provided by a synchrotron storage ring, and the dynamical information about desorption products is obtained from optical measurements of the quantum states, yields and velocity distributions of neutral ground-state and excited-state atoms ejected from the surface of the irradiating material. These studies have shown that the dominant exit channels in photon-induced particle emission are those producing ground-state and excited-state neutral atoms. Using dynamical information about these desorbing neutral species, obtained, for example, by laser-induced fluorescence and laser Doppler spectroscopy, we are generating an increasingly comprehensive picture of the dynamics of electronic energy flow into and out of pure crystalline surfaces in these prototypical dielectrics. We are also beginning to be able to relate desorption dynamics to specific materials properties, and to discriminate between pure surface and near-surface effects in these materials. Applications of these techniques to the problem of photon-induced surface damage and to analysis of surface dynamics in dielectric materials are discussed, and the relationships between these nearly ideal model materials and the non-crystalline, covalently bonded materials more typical of real optical elements are pointed out. 19 refs., 13 figs.

• Research Organization: Vanderbilt Univ., Nashville, TN (USA). Dept. of Physics and Astronomy
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5496576
• Report Number(s): LA-UR-86-2369; CONF-860880-17; ON: DE86013852
• Country of Publication: United States
• Language: English

Related Subjects

640301* -- Atomic
Molecular & Chemical Physics-- Beams & their Reactions
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALKALI METAL COMPOUNDS
CHLORINE COMPOUNDS
CRYSTALS
DATA
DESORPTION
ELECTROMAGNETIC RADIATION
EXPERIMENTAL DATA
FLUORESCENCE
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
INFORMATION
LASER SPECTROSCOPY
LITHIUM COMPOUNDS
LITHIUM FLUORIDES
LITHIUM HALIDES
LUMINESCENCE
NUMERICAL DATA
RADIATIONS
SODIUM COMPOUNDS
SPECTROSCOPY
SURFACE PROPERTIES
ULTRAVIOLET RADIATION