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Etude expérimentale des processus multi-électroniques lors de collisions d'ions en incidence rasante sur une surface de LiF(001)

Abstract : This manuscript deals with different experimental studies on grazing incidence (< 3 degrees) collisions of monocharged ions at low energies (< 3 keV). The incident beam is chopped. Deflection plates allow a charge analysis of scattered particles after collision detected on a position sensitive detector. Secondary particles (electrons and ions) are collected on a 2p detector made of 16 detection units (2 microchannel plates) Energy loss measurement (translational spectroscopy) associated to the detection of scattered particles in coincidence with secondary electrons emitted during the collision of neon lead to characterization of excited states of the target. Theses excited surface states, when localised at one halogen site are namely excitons and when localised at two holes are kwon as trions. This is the first characterisation of these states by ion impact at surfaces. For neon ions the capture is mediated by Auger neutralisation. Fluorine atoms collision confirmed the established threshold behaviour for the formation of negative fluorine ions. For positive incident fluorine, observation of negative ions under this threshold is an experimental evidence that double capture occurs at least under this threshold. According to the energy loss, interaction between two holes left at neighbouring sites on the surface is obvious. The statistical correlation is accompanied by spatial correlation where electron captures are made into neighbouring halogen sites. There is no experimental evidence to distinguish between bi-electronic capture and second order mono-electronic capture. A theoretical study seems to indicate that second order transition dominates the interaction.
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https://tel.archives-ouvertes.fr/tel-00261608
Contributor : Anouchah Momeni <>
Submitted on : Friday, March 7, 2008 - 4:16:40 PM
Last modification on : Thursday, December 10, 2020 - 11:07:06 AM
Long-term archiving on: : Friday, September 28, 2012 - 10:52:23 AM

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  • HAL Id : tel-00261608, version 1

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Anouchah Momeni. Etude expérimentale des processus multi-électroniques lors de collisions d'ions en incidence rasante sur une surface de LiF(001). Physique Atomique [physics.atom-ph]. Université Pierre et Marie Curie - Paris VI, 2003. Français. ⟨tel-00261608⟩

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