{"id":61174,"date":"2023-12-05T09:57:47","date_gmt":"2023-12-05T07:57:47","guid":{"rendered":"https:\/\/www.iemn.fr\/?p=61174"},"modified":"2023-12-05T10:02:07","modified_gmt":"2023-12-05T08:02:07","slug":"seminaire-aseem-rajan-kshirsagar","status":"publish","type":"post","link":"https:\/\/www.iemn.fr\/en\/agenda\/seminaire-aseem-rajan-kshirsagar.html","title":{"rendered":"S\u00e9minaire Aseem Rajan KSHIRSAGAR : \u2018Light tunable gas adsorption in functionalised metal-organic frameworks: insights from ab initio methods\u2019"},"content":{"rendered":"<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-msxs3a-c664474fb05f5aac0ebc35a4da183e6f\">\n.flex_column.av-msxs3a-c664474fb05f5aac0ebc35a4da183e6f{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-msxs3a-c664474fb05f5aac0ebc35a4da183e6f av_one_full  avia-builder-el-0  el_before_av_textblock  avia-builder-el-first  first flex_column_div av-zero-column-padding'     ><section  class='av_textblock_section av-lps1pweh-7e0affcf25b011210be97a220925c780'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h1>Aseem Rajan KSHIRSAGAR seminar<\/h1>\n<\/div><\/section><br \/>\n<section  class='av_textblock_section av-lps1pweh-7e0affcf25b011210be97a220925c780'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h5>January 8 at 11:00 am, in the LCI boardroom<\/h5>\n<\/div><\/section><\/p><\/div><section  class='av_textblock_section av-lps1r90k-4cec6d31f7714a3db2b40a8b092776cc'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p><strong>Part 1: Light tunable gas adsorption in functionalised metal-organic frameworks: insights from ab initio methods<\/strong><\/p>\n<p>Metal-organic frameworks (MOFs), crystalline hybrid porous materials made up of organic linkers and metal nodes, constitute an important family of candidate materials for carbon capture. MOFs functionalized with azobenzene, a photo-isomerising molecule, are capable of light stimulated capture and release of CO2. The use of light as a stimulus, in this case, can reduce greatly the energy costs of the carbon capture. Using atomistic modeling, we reveal the microscopic mechanism behind light-tunable gas uptake in azobenzene functionalised MOF-5 to be the blocking and unblocking of the metal-node, by distinct geometric configurations of azobenzene. Further, we shed light on the electronic excitations in the functionalised MOF to propose strategies for achieving high yields of photo-isomerisation. Our study also shows that electronic excitations in prototype MOF-5 give rise to strongly bound states of electron-hole pair, analogous to organic insulators.<\/p>\n<p><strong>Part 2: Modulation of magnetization in BiFeO3\u00a0using circularly polarized light<\/strong><\/p>\n<p>BiFeO3\u00a0is a multiferroic material featuring ferroelectricity and noncollinear antiferromagnetism. Dynamic and efficient control of the characteristic spin texture of BiFeO3\u00a0is attractive for emerging quantum devices. Crystal-field d \u2192 d excitations localised on Fe atomic sites in BiFeO3\u00a0induce a complex interplay among the spin, charge and lattice degrees of freedom, making them relevant for manipulation of the spin texture. In this work,\u00a0ab initio\u00a0methods based on the\u00a0GW\u00a0approximation and the Bethe-Salpeter equation are used to characterize localised spin-flip excitations within Fe-3d shell. These excitations are strongly bound and appear deep within the electronic gap. Their spin-content and strong localisation are protected by the d5\u00a0antiferromagnetic ordering. The underlying crystal symmetry gives rise to chiral spin-flip exciton states localized on distinct Fe centers which possess net angular momentum of \u00b1h\/2\u03c0. These chiral excitons couple selectively to light of a particular circular polarisation and are confined to a particular Fe magnetic sub-lattice. As a consequence, net spin-magnetisation can be achieved using circularly polarised light coupling with exciton of desired chirality, thereby modulating the antiferromagnetic texture and giving rise to transient ferrimagnetism.<\/p>\n<\/div><\/section><\/p>","protected":false},"excerpt":{"rendered":"","protected":false},"author":2,"featured_media":61178,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[87,65,84],"tags":[],"class_list":["post-61174","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-agenda-en","category-agenda","category-agenda-en-en"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/61174","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/comments?post=61174"}],"version-history":[{"count":0,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/61174\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media\/61178"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=61174"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/categories?post=61174"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/tags?post=61174"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}