{"584613":{"#nid":"584613","#data":{"type":"event","title":"Freezing on a Sphere ","body":[{"value":"\u003Ch3\u003E\u003Cstrong\u003ESoft Matter Incubator Distinguished Lecture Series: Prof. Paul Chaikin, New York University\u003C\/strong\u003E\u003C\/h3\u003E\r\n\r\n\u003Cp\u003EMelting in two dimensions is characterized by the thermal excitation and proliferation of free topological defects, disclinations and dislocations which destroy the rigidity of the crystal. This freezing\/melting process has been well established for flat systems especially for dipolar, U(r) ~1\/r3potentials, with control parameter, \u0026Gamma; = U(a)\/kBT, where a is an interparticle spacing.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe flat spacing freezing occurs at \u0026Gamma; ~ 70. On a sphere topology requires that there must be a net 12 pentagons (1\/2 disclinations) i.e. the 12 pentagons on a soccer ball, and energetically it is favorable to screen the pentagons with strings of dislocations (pentagon-heptagon pairs) known as \u0026ldquo;scars\u0026rdquo;.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EOur system consists of charged colloidal particles in an oil droplet in water bound to the inner surface by image charges. We study particle mean square displacement, hexagonal order, defect structure, and scar-scar correlations by confocal microscopy for droplets of different \u0026Gamma; and number of particles.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EFreezing on sphere proceeds by the formation of a single, encompassing, crystalline \u0026ldquo;continent\u0026rdquo; that forces the defects into 12 isolated \u0026ldquo;seas\u0026rdquo; with icosahedral symmetry at the flat space value of \u0026Gamma; ~ 70.\u003C\/p\u003E\r\n","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"Freezing on a Sphere "}],"uid":"27664","created_gmt":"2016-12-05 15:45:09","changed_gmt":"2017-04-13 21:13:43","author":"Alison Morain","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2016-12-07T15:00:00-05:00","event_time_end":"2016-12-07T16:00:00-05:00","event_time_end_last":"2016-12-07T16:00:00-05:00","gmt_time_start":"2016-12-07 20:00:00","gmt_time_end":"2016-12-07 21:00:00","gmt_time_end_last":"2016-12-07 21:00:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"hg_media":{"584614":{"id":"584614","type":"image","title":"Paul Chaikin","body":null,"created":"1480952854","gmt_created":"2016-12-05 15:47:34","changed":"1480952854","gmt_changed":"2016-12-05 15:47:34","alt":"","file":{"fid":"222899","name":"SMI Distingished Lecture Series - Chaikin (003).jpg","image_path":"\/sites\/default\/files\/images\/SMI%20Distingished%20Lecture%20Series%20-%20Chaikin%20%28003%29.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/SMI%20Distingished%20Lecture%20Series%20-%20Chaikin%20%28003%29.jpg","mime":"image\/jpeg","size":21739,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/SMI%20Distingished%20Lecture%20Series%20-%20Chaikin%20%28003%29.jpg?itok=KQZj_yhR"}}},"media_ids":["584614"],"groups":[{"id":"126011","name":"School of Physics"}],"categories":[],"keywords":[{"id":"166937","name":"School of Physics"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1795","name":"Seminar\/Lecture\/Colloquium"}],"invited_audience":[{"id":"78761","name":"Faculty\/Staff"},{"id":"78751","name":"Undergraduate students"},{"id":"174045","name":"Graduate students"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003Eamorain@gatech.edu\u003C\/p\u003E\r\n","format":"limited_html"}],"email":[],"slides":[],"orientation":[],"userdata":""}}}