{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/22275"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/22275","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Which way did it go? Revisiting the time-resolved study of bromine atom and iodine molecule","abstract":"The low collision energy interaction of Br($\\rm\\sp 2P\\sb {3/2}$) (Br) or Br($\\rm\\sp 2P\\sb {1/2}$)(Br$\\sp {*}$) and I$\\sb 2$ is studied in real time. The method of detection, Resonance Enhanced Multiphoton Ionization (REMPI)-Time of Flight Mass Spectroscopy (TOFMS), allows unambiguous identification of products. The interaction is initiated in a restricted region of phase space defined by the geometry of the precursor dimer, H(D)Br$\\rm\\sp {*}I\\sb 2$. The photodissociation of H(D)Br provides both Br and Br$\\sp {*}$. The combination of low collision energy and narrow distribution of initial conditions results in a metastable intermediate complex, $\\rm I\\sb 2Br\\sp {*}$. We simultaneously detect two transients, one of which is consistent with the above mentioned complex undergoing an internal conversion to either the ground or 1$\\rm\\sp {st}$ excited state. The second transient may contain a contribution from the ground state reaction, Br+I$\\sb 2$, but interference from other channels makes this transient difficult to assign. Both transients' risetimes vary as a function of precursor constitution, i.e. H(D)Br$\\rm\\sp {*}I\\sb 2$, a feature that is readily explained by a simple 1$\\rm\\sp {st}$ order kinetic model.","abstract_html":"The low collision energy interaction of Br($\\rm\\sp 2P\\sb {3/2}$) (Br) or Br($\\rm\\sp 2P\\sb {1/2}$)(Br$\\sp {*}$) and I$\\sb 2$ is studied in real time. The method of detection, Resonance Enhanced Multiphoton Ionization (REMPI)-Time of Flight Mass Spectroscopy (TOFMS), allows unambiguous identification of products. The interaction is initiated in a restricted region of phase space defined by the geometry of the precursor dimer, H(D)Br$\\rm\\sp {*}I\\sb 2$. The photodissociation of H(D)Br provides both Br and Br$\\sp {*}$. The combination of low collision energy and narrow distribution of initial conditions results in a metastable intermediate complex, $\\rm I\\sb 2Br\\sp {*}$. We simultaneously detect two transients, one of which is consistent with the above mentioned complex undergoing an internal conversion to either the ground or 1$\\rm\\sp {st}$ excited state. The second transient may contain a contribution from the ground state reaction, Br+I$\\sb 2$, but interference from other channels makes this transient difficult to assign. Both transients' risetimes vary as a function of precursor constitution, i.e. H(D)Br$\\rm\\sp {*}I\\sb 2$, a feature that is readily explained by a simple 1$\\rm\\sp {st}$ order kinetic model.","abstract_has_math":true,"creators":["Tuchler, Matthew Frederick"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Chemistry","degree_department":null,"school":null,"contributors":["McDonald, J. Douglas"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T13:34:41Z","date_published":"2011-05-07T13:34:41Z","updated_at":"2026-07-22T22:25:19Z","subjects":["Chemistry, Physical"],"languages":["eng"],"rights":["Copyright 1995 Tuchler, Matthew Frederick"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9624521","(UMI)AAI9624521"],"render_values":[{"text":"AAI9624521","href":null,"code":true},{"text":"(UMI)AAI9624521","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/22275","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["McDonald, J. Douglas"]},{"key":"dc:creator","label":"Author","values":["Tuchler, Matthew Frederick"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T13:34:41Z","10000-01-01","1995"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemistry"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemistry, Physical"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1995 Tuchler, Matthew Frederick"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9624521","(UMI)AAI9624521","http://hdl.handle.net/2142/22275"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The low collision energy interaction of Br($\\rm\\sp 2P\\sb {3/2}$) (Br) or Br($\\rm\\sp 2P\\sb {1/2}$)(Br$\\sp {*}$) and I$\\sb 2$ is studied in real time. The method of detection, Resonance Enhanced Multiphoton Ionization (REMPI)-Time of Flight Mass Spectroscopy (TOFMS), allows unambiguous identification of products. The interaction is initiated in a restricted region of phase space defined by the geometry of the precursor dimer, H(D)Br$\\rm\\sp {*}I\\sb 2$. The photodissociation of H(D)Br provides both Br and Br$\\sp {*}$. The combination of low collision energy and narrow distribution of initial conditions results in a metastable intermediate complex, $\\rm I\\sb 2Br\\sp {*}$. We simultaneously detect two transients, one of which is consistent with the above mentioned complex undergoing an internal conversion to either the ground or 1$\\rm\\sp {st}$ excited state. The second transient may contain a contribution from the ground state reaction, Br+I$\\sb 2$, but interference from other channels makes this transient difficult to assign. Both transients' risetimes vary as a function of precursor constitution, i.e. H(D)Br$\\rm\\sp {*}I\\sb 2$, a feature that is readily explained by a simple 1$\\rm\\sp {st}$ order kinetic model.","An estimate of the precursor structure is provided and used as a starting point for a series of trajectory calculations run on standard LEPS surfaces. The trajectory calculations were used to study the process initiated on the spin-orbit excited (SO) surface, Br$\\sp {*}$+I$\\sb 2$. At various times during the evolution on the SO surface, the trajectory is allowed to internally convert to a lower electronic surface. The trajectory is followed to completion, at which point a thorough analysis of the products is conducted. The results of these trajectory studies are presented and discussed in detail, including a prediction that the method of detection may result in a signal arising from more than one dynamic feature of the complex evolution.","Made available in DSpace on 2011-05-07T13:34:41Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9624521.pdf: 5579547 bytes, checksum: 78e39ab30959912e5e59d410590507ca (MD5) Previous issue date: 1995","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:56:31Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:26:25-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Which way did it go? Revisiting the time-resolved study of bromine atom and iodine molecule"]}]}],"canonical_facts":{"dc:contributor":["McDonald, J. Douglas"],"dc:creator":["Tuchler, Matthew Frederick"],"dc:date":["2011-05-07T13:34:41Z","10000-01-01","1995"],"dc:description":["The low collision energy interaction of Br($\\rm\\sp 2P\\sb {3/2}$) (Br) or Br($\\rm\\sp 2P\\sb {1/2}$)(Br$\\sp {*}$) and I$\\sb 2$ is studied in real time. The method of detection, Resonance Enhanced Multiphoton Ionization (REMPI)-Time of Flight Mass Spectroscopy (TOFMS), allows unambiguous identification of products. The interaction is initiated in a restricted region of phase space defined by the geometry of the precursor dimer, H(D)Br$\\rm\\sp {*}I\\sb 2$. The photodissociation of H(D)Br provides both Br and Br$\\sp {*}$. The combination of low collision energy and narrow distribution of initial conditions results in a metastable intermediate complex, $\\rm I\\sb 2Br\\sp {*}$. We simultaneously detect two transients, one of which is consistent with the above mentioned complex undergoing an internal conversion to either the ground or 1$\\rm\\sp {st}$ excited state. The second transient may contain a contribution from the ground state reaction, Br+I$\\sb 2$, but interference from other channels makes this transient difficult to assign. Both transients' risetimes vary as a function of precursor constitution, i.e. H(D)Br$\\rm\\sp {*}I\\sb 2$, a feature that is readily explained by a simple 1$\\rm\\sp {st}$ order kinetic model.","An estimate of the precursor structure is provided and used as a starting point for a series of trajectory calculations run on standard LEPS surfaces. The trajectory calculations were used to study the process initiated on the spin-orbit excited (SO) surface, Br$\\sp {*}$+I$\\sb 2$. At various times during the evolution on the SO surface, the trajectory is allowed to internally convert to a lower electronic surface. The trajectory is followed to completion, at which point a thorough analysis of the products is conducted. The results of these trajectory studies are presented and discussed in detail, including a prediction that the method of detection may result in a signal arising from more than one dynamic feature of the complex evolution.","Made available in DSpace on 2011-05-07T13:34:41Z (GMT). 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Revisiting the time-resolved study of bromine atom and iodine molecule"],"dc:type":["text"],"thesis:degree_discipline":["Chemistry"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:19Z"}