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Calcul prédictif du facteur de partage isotopique entre minéraux dans le cadre de la théorie de la fonctionnelle de la densité

Abstract : In this work, we applied electronic structure calculations based on density functional theory to compute oxygen, hydrogen and silicon fractionation properties between several materials of interest in Earth Sciences. Understanding of such mechanisms is a main objective in geochemistry, since the isotopic content of minerals is a witness of geochemical events. Electronic structure calculations enables the determination of the complete vibrational properties of one material at the harmonic level, from which its fractionation properties can be deduced. Our goal is to validate an ab initio approach, i.e. free from any parameter coming from experiment, enaling the prediction of the fractionation between two minerals. We studied the materials: quartz, gas water, ice, kaolinite, lizardite, enstatite, forsterite, brucite and gibbsite. Some of them have been the subject of precise experimental studies of their various physical properties, which permits us to validate our approach, and all are of main interest in Earth Sciences, which permits us to propose new fractionation laws as a function of temperature, and to check the validity of laws existing in the litterature. This is the first time that such a systematic study, based on ab initio approaches, is realized on so many different systems. That is why we realized the possibly most complete study of the possible sources of error in our calculation. Moreover, this approach enables detailed analysis of the physical processes driving isotopic fractionation.
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https://tel.archives-ouvertes.fr/tel-00231076
Contributor : Merlin Méheut <>
Submitted on : Friday, February 1, 2008 - 1:40:27 AM
Last modification on : Wednesday, December 9, 2020 - 3:10:31 PM
Long-term archiving on: : Monday, May 3, 2010 - 6:00:36 PM

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  • HAL Id : tel-00231076, version 1

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Merlin Méheut-Le Quéau. Calcul prédictif du facteur de partage isotopique entre minéraux dans le cadre de la théorie de la fonctionnelle de la densité. Physique [physics]. Université Pierre et Marie Curie - Paris VI, 2008. Français. ⟨tel-00231076⟩

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