{"id":19433,"date":"2018-02-23T16:54:24","date_gmt":"2018-02-23T16:54:24","guid":{"rendered":"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=19433"},"modified":"2018-02-25T08:40:28","modified_gmt":"2018-02-25T08:40:28","slug":"is-h%ce%bd3-an-allotrope-of-light","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19433","title":{"rendered":"Is  (h\u03bd)3 an allotrope of light?"},"content":{"rendered":"<div class=\"kcite-section\" kcite-section-id=\"19433\">\n<p>A little while ago I pondered <a href=\"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=13987\">allotropic bromine<\/a>, or Br(Br)<sub>3<\/sub>. But this is a far wackier report<span id=\"cite_ITEM-19433-0\" name=\"citation\"><a href=\"#ITEM-19433-0\">[1]<\/a><\/span> of <i>a molecule of light.<\/i><\/p>\n<p>The preparation and detection of dimer and trimer bound photon states is pure physics; probably considered by the physicists themselves as NOT chemistry. It is certainly true, as a chemist, \u00a0that I understood only a little of the article. But chemistry uses photons extensively in the area we call photochemistry. We represent photons as\u00a0h\u03bd, and hence (h\u03bd)<sub>3<\/sub>.<\/p>\n<p>This molecular light has some fascinating properties. One is that it travels around 100,000 times slower than the usual speed of light. Another is the estimate of the photon-photon binding energies, which are ~10<sup>10<\/sup> times smaller than in diatomic\u00a0molecules such as NaCl and H<sub>2<\/sub>. I await with interest to see whether this new state of light will achieve any interesting chemistry.<\/p>\n<h2>References<\/h2>\n    <ol class=\"kcite-bibliography csl-bib-body\"><li id=\"ITEM-19433-0\">Q. Liang, A.V. Venkatramani, S.H. Cantu, T.L. Nicholson, M.J. Gullans, A.V. Gorshkov, J.D. Thompson, C. Chin, M.D. Lukin, and V. Vuleti\u0107, \"Observation of three-photon bound states in a quantum nonlinear medium\", <i>Science<\/i>, vol. 359, pp. 783-786, 2018. <a href=\"https:\/\/doi.org\/10.1126\/science.aao7293\">https:\/\/doi.org\/10.1126\/science.aao7293<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> <!-- kcite-section 19433 -->","protected":false},"excerpt":{"rendered":"<p>A little while ago I pondered allotropic bromine, or Br(Br)3. But this is a far wackier report of a molecule of light. The preparation and detection of dimer and trimer bound photon states is pure physics; probably considered by the physicists themselves as NOT chemistry. It is certainly true, as a chemist, \u00a0that I understood [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"activitypub_content_warning":"","activitypub_content_visibility":"","activitypub_max_image_attachments":5,"activitypub_interaction_policy_quote":"anyone","activitypub_status":"","footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[4],"tags":[2329,1436,2328,224,1395,2008,1441,1433],"ppma_author":[2661],"class_list":["post-19433","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry","tag-atomic-physics","tag-bromine","tag-bromine-compounds","tag-chemist","tag-chemistry","tag-halogens","tag-hypobromite","tag-oxidizing-agents"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.8 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Is (h\u03bd)3 an allotrope of light? - Henry Rzepa&#039;s Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19433\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Is (h\u03bd)3 an allotrope of light? - Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"og:description\" content=\"A little while ago I pondered allotropic bromine, or Br(Br)3. But this is a far wackier report of a molecule of light. The preparation and detection of dimer and trimer bound photon states is pure physics; probably considered by the physicists themselves as NOT chemistry. It is certainly true, as a chemist, \u00a0that I understood [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19433\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"article:published_time\" content=\"2018-02-23T16:54:24+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2018-02-25T08:40:28+00:00\" \/>\n<meta name=\"author\" content=\"Henry Rzepa\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Henry Rzepa\" \/>\n\t<meta name=\"twitter:label2\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Is (h\u03bd)3 an allotrope of light? - Henry Rzepa&#039;s Blog","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19433","og_locale":"en_GB","og_type":"article","og_title":"Is (h\u03bd)3 an allotrope of light? - Henry Rzepa&#039;s Blog","og_description":"A little while ago I pondered allotropic bromine, or Br(Br)3. 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I noticed that several searches on this topic which led people to this post also included a query about\u00a0the differences between it and the bromine analogue. For those who posed this question, here is\u2026","rel":"","context":"In &quot;Interesting chemistry&quot;","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":13987,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=13987","url_meta":{"origin":19433,"position":1},"title":"Allotropic halogens.","author":"Henry Rzepa","date":"April 26, 2015","format":false,"excerpt":"Allotropes are differing structural forms of the elements. The best known example is that of carbon, which comes as diamond and graphite, along with the relatively recently discovered fullerenes and now graphenes. Here I ponder whether any of the halogens can have allotropes. Firstly, I am not aware of much\u2026","rel":"","context":"In &quot;reaction mechanism&quot;","block_context":{"text":"reaction mechanism","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1086"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":7964,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7964","url_meta":{"origin":19433,"position":2},"title":"Text-books and the bromination of ethene.","author":"Henry Rzepa","date":"October 14, 2012","format":false,"excerpt":"There is often a disconnect between how a text-book (schematically) represents a reaction and a more quantitive \"reality\" revealed by quantum mechanics. Is the bromination of ethene to give 1,2-dibromoethane one such example? Text-books will show how ethene interacts with bromine to form a cyclic bromonium cation, which with the\u2026","rel":"","context":"In &quot;Interesting chemistry&quot;","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/10\/Br2b2.gif?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":13488,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=13488","url_meta":{"origin":19433,"position":3},"title":"How many water molecules does it take to ionise HI?","author":"Henry Rzepa","date":"February 28, 2015","format":false,"excerpt":"Why is this post orphaned from the previous? In order to have the opportunity of noting that treating iodine computationally can be a little different from the procedures used for F, Cl and Br. As the nuclear charge increases proceeding down the periodic table, the inner electron shells start becoming\u2026","rel":"","context":"In &quot;General&quot;","block_context":{"text":"General","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":4375,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=4375","url_meta":{"origin":19433,"position":4},"title":"More is more: the dyotropic rearrangement of 1,2-dibromoethane.","author":"Henry Rzepa","date":"June 12, 2011","format":false,"excerpt":"In the previous post, \u00a0I discussed what we could learn from ethane by forcing it into a pericyclic dyotropic rearrangement. We saw how it voraciously scavenged two electrons from the \u00a0C-C bond to achieve this. What if we give it more electrons? Thus 1,2-dibromoethane undergoing the same reaction. Subjected to\u2026","rel":"","context":"In \"dibromoethane\"","block_context":{"text":"dibromoethane","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?tag=dibromoethane"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/06\/dyobr.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":7580,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7580","url_meta":{"origin":19433,"position":5},"title":"The Sn2 reaction and the anomaly of carbon.","author":"Henry Rzepa","date":"September 6, 2012","format":false,"excerpt":"It was three years ago that I first blogged on the topic of the Sn2 reaction. Matthias Bickelhaupt had suggested that the Sn2 reaction involving displacement at a carbon atom was an anomaly; the true behaviour was in fact exhibited by the next element down in the series, silicon. The\u2026","rel":"","context":"In &quot;Interesting chemistry&quot;","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/09\/sn2-Na1.gif?resize=350%2C200","width":350,"height":200},"classes":[]}],"jetpack_likes_enabled":false,"authors":[{"term_id":2661,"user_id":1,"is_guest":0,"slug":"admin","display_name":"Henry Rzepa","avatar_url":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","author_category":"1","first_name":"Henry","last_name":"Rzepa","user_url":"https:\/\/orcid.org\/0000-0002-8635-8390","job_title":"","description":"Henry Rzepa is Emeritus Professor of Computational Chemistry at Imperial College London."}],"_links":{"self":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/19433","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=19433"}],"version-history":[{"count":2,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/19433\/revisions"}],"predecessor-version":[{"id":19435,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/19433\/revisions\/19435"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=19433"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=19433"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=19433"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=19433"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}