<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="static/style.xsl"?><OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd"><responseDate>2026-09-20T18:07:00Z</responseDate><request verb="GetRecord" identifier="oai:dspace.mit.edu:1721.1/36261" metadataPrefix="dim">https://dspace.mit.edu/server/oai/request</request><GetRecord><record><header><identifier>oai:dspace.mit.edu:1721.1/36261</identifier><datestamp>2026-06-11T14:03:30Z</datestamp><setSpec>com_1721.1_7582</setSpec><setSpec>com_1721.1_7581</setSpec><setSpec>col_1721.1_131022</setSpec></header><metadata><dim:dim xmlns:dim="http://www.dspace.org/xmlns/dspace/dim" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:doc="http://www.lyncode.com/xoai" xsi:schemaLocation="http://www.dspace.org/xmlns/dspace/dim http://www.dspace.org/schema/dim.xsd">
   <dim:field mdschema="dc" element="contributor" qualifier="advisor" lang="en_US">Robert W. Field.</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="author" lang="en_US">Thom, Ryan L. (Ryan Louis), 1978-</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="other" lang="en_US">Massachusetts Institute of Technology. Dept. of Chemistry.</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="department">Massachusetts Institute of Technology. Department of Chemistry</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="accessioned">2008-02-28T16:28:16Z</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="available">2008-02-28T16:28:16Z</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="copyright" lang="en_US">2006</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="issued" lang="en_US">2006</dim:field>
   <dim:field mdschema="dc" element="identifier" qualifier="uri">http://hdl.handle.net/1721.1/36261</dim:field>
   <dim:field mdschema="dc" element="identifier" qualifier="oclc" lang="en_US">77461671</dim:field>
   <dim:field mdschema="dc" element="description" lang="en_US">Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2006.</dim:field>
   <dim:field mdschema="dc" element="description" lang="en_US">Vita.</dim:field>
   <dim:field mdschema="dc" element="description" lang="en_US">Includes bibliographical references (p. 93-96).</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="abstract" lang="en_US">A multispectral study employing both Ultraviolet Laser Induced Fluorescence (UV-LIF) and Surface Electron Ejection by Laser Excited Metastables (SEELEM) spectroscopies has yielded a complete characterization of singlet-triplet interactions relevant to intersystem crossing in the region of the 3v3 vibrational level of the A 1A, excited electronic state of acetylene. Intersystem crossing proceeds through a "doorway" state which has been plausibly assigned as a specific low-lying vibrational level of the third triplet electronic state, T3. The predominantly T1,2 dark states observed in the SEELEM spectrum show the remarkable property of spectral regularity, in the sense that they are able to be arranged into smooth, well-behaved "vibrational levels" as judged from reduced rotational term value plots. This fact, together with the observation of essentially all the expected triplet density of states, strongly suggest that these triplet states fall into the "strongly coupled," highly mixed regime.</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="statementofresponsibility" lang="en_US">by Ryan L. Thom.</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="degree" lang="en_US">Ph.D.</dim:field>
   <dim:field mdschema="dc" element="format" qualifier="extent" lang="en_US">97 p.</dim:field>
   <dim:field mdschema="dc" element="language" qualifier="iso" lang="en_US">eng</dim:field>
   <dim:field mdschema="dc" element="publisher" lang="en_US">Massachusetts Institute of Technology</dim:field>
   <dim:field mdschema="dc" element="rights" lang="en_US">M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.</dim:field>
   <dim:field mdschema="dc" element="rights" qualifier="uri">http://dspace.mit.edu/handle/1721.1/7582</dim:field>
   <dim:field mdschema="dc" element="subject" lang="en_US">Chemistry.</dim:field>
   <dim:field mdschema="dc" element="title" lang="en_US">Spectroscopic investigations of intersystem crossing and triplet state structure in acetylene</dim:field>
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   	&lt;Title>Spectroscopic investigations of intersystem crossing and triplet state structure in acetylene&lt;/Title>
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   	&lt;PublicationDate>2006&lt;/PublicationDate>
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        	&lt;DisplayName>Thom, Ryan L. (Ryan Louis), 1978-&lt;/DisplayName>
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            &lt;DisplayName>Massachusetts Institute of Technology&lt;/DisplayName>
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    &lt;Keyword>Chemistry.&lt;/Keyword>
   	&lt;Abstract>A multispectral study employing both Ultraviolet Laser Induced Fluorescence (UV-LIF) and Surface Electron Ejection by Laser Excited Metastables (SEELEM) spectroscopies has yielded a complete characterization of singlet-triplet interactions relevant to intersystem crossing in the region of the 3v3 vibrational level of the A 1A, excited electronic state of acetylene. Intersystem crossing proceeds through a &amp;quot;doorway&amp;quot; state which has been plausibly assigned as a specific low-lying vibrational level of the third triplet electronic state, T3. The predominantly T1,2 dark states observed in the SEELEM spectrum show the remarkable property of spectral regularity, in the sense that they are able to be arranged into smooth, well-behaved &amp;quot;vibrational levels&amp;quot; as judged from reduced rotational term value plots. This fact, together with the observation of essentially all the expected triplet density of states, strongly suggest that these triplet states fall into the &amp;quot;strongly coupled,&amp;quot; highly mixed regime.&lt;/Abstract>
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