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Microscopie de photodétachement de Si- et OH-. Spectroscopie microeV par imagerie de fonction d'onde pour un test de validité du modèle de l'électron libre

Abstract : The photodetachment microscope was built in the middle of the nineties at Laboratory Aimé Cotton. It enables one to record interference patterns due to electrons detached from negative ions by a laser into a uniform electric field. In a first approximation, the previously linked electron and neutral species don't interact any more after detachment : we have a free electron source. According to the classical equations of movement, a free electron placed in a uniform electric field with a given kinetic energy has two different trajectories for going to a given point. In a quantum point of view, the electronic matter wave is divided into two parts, which follow both possible ways. As the electronic wave emitted by photodetachment is coherent, these two half-waves interfere. The recorded interference patterns are highly sensitive to the electron kinetic energy, which can thus be measured by comparison between the experimental data and the free electron model predictions. These high resolution spectroscopy measurements were used for testing the free electron model validity for the Si- and OH- anions, looking for possible interaction effects between the detached electron and the neutral species. The Si- anion enables us to show the validity of the method for an atom heavier than those previously studied. The OH- molecular anion was chosen for examining the dipolar potential effect on the interference images. We didn't see any modification of the images, and the obtained results validated this method for the measurements of diatomic anion detachment energies. These researches provided new values for the electron affinities of Si and OH, with an improved accuracy.
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https://tel.archives-ouvertes.fr/tel-00004059
Contributor : Fabienne Goldfarb <>
Submitted on : Thursday, December 25, 2003 - 6:21:29 PM
Last modification on : Wednesday, October 14, 2020 - 3:41:50 AM
Long-term archiving on: : Friday, April 2, 2010 - 7:55:27 PM

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  • HAL Id : tel-00004059, version 1

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Fabienne Goldfarb. Microscopie de photodétachement de Si- et OH-. Spectroscopie microeV par imagerie de fonction d'onde pour un test de validité du modèle de l'électron libre. Physique Atomique [physics.atom-ph]. Université Paris Sud - Paris XI, 2003. Français. ⟨tel-00004059⟩

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