{"id":29850,"date":"2021-12-28T00:32:21","date_gmt":"2021-12-27T23:32:21","guid":{"rendered":"https:\/\/karmaka.de\/?p=29850"},"modified":"2021-12-28T00:32:21","modified_gmt":"2021-12-27T23:32:21","slug":"oxygen-and-magnesium-mass-independent-isotopic-fractionation-induced-by-chemical-reactions-in-plasma","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=29850","title":{"rendered":"Oxygen and magnesium mass-independent isotopic fractionation induced by chemical reactions in plasma<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Fran\u00e7ois Robert, Marc Chaussidon, Adriana Gonzalez-Cano, and Smail Mostefaoui<\/p>\n\n\n\n<p>PNAS December 28, 2021 118 (52)<\/p>\n\n\n\n<p><a href=\"https:\/\/www.pnas.org\/content\/118\/52\/e2114221118\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br><a href=\"https:\/\/www.pnas.org\/content\/pnas\/118\/52\/e2114221118.full.pdf\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p>&#8220;Abstract<\/p>\n\n\n\n<p class=\"justify-text\">Enrichment or depletion ranging from \u221240 to +100% in the major isotopes 16O and 24Mg were observed experimentally in solids condensed from carbonaceous plasma composed of CO2\/MgCl2\/Pentanol or N2O\/Pentanol for O and MgCl2\/Pentanol for Mg. In NanoSims imaging, isotope effects appear as micrometer-size hotspots embedded in a carbonaceous matrix showing no isotope fractionation. For Mg, these hotspots are localized in carbonaceous grains, which show positive and negative isotopic effects so that the whole grain has a standard isotope composition. For O, no specific structure was observed at hotspot locations. These results suggest that MIF (mass-independent fractionation) effects can be induced by chemical reactions taking place in plasma. The close agreement between the slopes of the linear correlations observed between \u03b425Mg versus \u03b426Mg and between \u03b417O versus \u03b418O and the slopes calculated using the empirical MIF factor \u03b7 discovered in ozone [M. H. Thiemens, J. E. Heidenreich, III. Science 219, 1073\u20131075; C. Janssen, J. Guenther, K. Mauersberger, D. Krankowsky. Phys. Chem. Chem. Phys. 3, 4718\u20134721] attests to the ubiquity of this process. Although the chemical reactants used in the present experiments cannot be directly transposed to the protosolar nebula, a similar MIF mechanism is proposed for oxygen isotopes: at high temperature, at the surface of grains, a mass-independent isotope exchange could have taken place between condensing oxides and oxygen atoms originated form the dissociation of CO or H2O gas.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Fran\u00e7ois Robert, Marc Chaussidon, Adriana Gonzalez-Cano, and Smail Mostefaoui PNAS December 28, 2021 118 (52) LINK (OPEN ACCESS)PDF (OPEN ACCESS) &#8220;Abstract Enrichment or depletion ranging from \u221240 to +100% in the major isotopes 16O and&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[72,65,71],"tags":[395,3701,2227,5493,1845,2766],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/29850"}],"collection":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=29850"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/29850\/revisions"}],"predecessor-version":[{"id":29851,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/29850\/revisions\/29851"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=29850"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=29850"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=29850"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}