{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/69234"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/69234","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Hot Band Rotational Relaxation Time in Carbonyl Sulfide by Transient Infrared-Microwave Double Resonance","abstract":"Rotational relaxation time (T) has been measured for pure Carbonyl Sulfide (('16)O('12)C('32)S) in a highly vibrationally and rotationally excited state (03('1f)0, J=24). A CO(,2) laser (P(,9)(24) line) was used to pulse excite the OCS gas: (01('1f)0, J=25) (--->) (03('1f)0, J=24). The resulting transient population difference between l doublet states, (03('1f)0, J=24) and 03('1e)0, J=24), was monitored with a microwave (7.4 GHz) probe signal. Individual transient infrared-microwave signals were analyzed and from the gain pulse shape it is concluded that population decay time (T(,1)) and polarization decay time (T(,2)) are approximately equal to a composite relaxation time (T). From the pressure dependence of T as pressure (p) changes from 0.04 to 0.3 Torr(5 to 40 Pa), it is concluded that (pT) = 32 ns(.)Torr = 4.3 (mu)s(.)Pa.","abstract_html":"Rotational relaxation time (T) has been measured for pure Carbonyl Sulfide (('16)O('12)C('32)S) in a highly vibrationally and rotationally excited state (03('1f)0, J=24). A CO(,2) laser (P(,9)(24) line) was used to pulse excite the OCS gas: (01('1f)0, J=25) (--->) (03('1f)0, J=24). The resulting transient population difference between l doublet states, (03('1f)0, J=24) and 03('1e)0, J=24), was monitored with a microwave (7.4 GHz) probe signal. Individual transient infrared-microwave signals were analyzed and from the gain pulse shape it is concluded that population decay time (T(,1)) and polarization decay time (T(,2)) are approximately equal to a composite relaxation time (T). From the pressure dependence of T as pressure (p) changes from 0.04 to 0.3 Torr(5 to 40 Pa), it is concluded that (pT) = 32 ns(.)Torr = 4.3 (mu)s(.)Pa.","abstract_has_math":false,"creators":["Leap, John William"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Electrical Engineering","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-15T19:04:20Z","date_published":"2014-12-15T19:04:20Z","updated_at":"2026-07-22T22:26:00Z","subjects":["Engineering, Electronics and Electrical"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8218505"],"render_values":[{"text":"(UMI)AAI8218505","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/69234","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Leap, John William"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-15T19:04:20Z","10000-01-01","1982"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical Engineering"]},{"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":["Engineering, Electronics and Electrical"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/69234","(UMI)AAI8218505"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Rotational relaxation time (T) has been measured for pure Carbonyl Sulfide (('16)O('12)C('32)S) in a highly vibrationally and rotationally excited state (03('1f)0, J=24). A CO(,2) laser (P(,9)(24) line) was used to pulse excite the OCS gas: (01('1f)0, J=25) (--->) (03('1f)0, J=24). The resulting transient population difference between l doublet states, (03('1f)0, J=24) and 03('1e)0, J=24), was monitored with a microwave (7.4 GHz) probe signal. Individual transient infrared-microwave signals were analyzed and from the gain pulse shape it is concluded that population decay time (T(,1)) and polarization decay time (T(,2)) are approximately equal to a composite relaxation time (T). From the pressure dependence of T as pressure (p) changes from 0.04 to 0.3 Torr(5 to 40 Pa), it is concluded that (pT) = 32 ns(.)Torr = 4.3 (mu)s(.)Pa.","The CO(,2) laser included a transversely excited atmospheric pressure (TEA) gain section and a low pressure, selective, saturable absorber (NH(,3)) inside the laser cavity. The frequency shifted and modulated multimode pulse from the CO(,2) laser was abruptly truncated with a plasma shutter breakdown switch so that the OCS gas could be observed in the absence of further infrared excitation. The truncated laser pulse was used to transiently excite OCS gas in a 3-meter long arm of a WR90 waveguide bridge with pierced E plane bends. The microwave frequency was tuned to resonance with the l doublet transition and the bridge was adjusted to be sensitive to amplitude changes. Envelope detection of the amplified bridge imbalance yielded a video signal proportional to microwave gain. The signal to noise of individual transients was adequate and signal averaging was not used. Waveforms were recorded photographically from an oscilloscope. Values of relaxation time (T) were obtained from the transient gain pulse width by using a Bloch equation model for the gas and by considering the bandwidth limits of the video amplifiers.","Made available in DSpace on 2014-12-15T19:04:20Z (GMT). No. of bitstreams: 1 8218505.pdf: 1693638 bytes, checksum: 0d204a11b872e2bd9a76fbd3d632dce0 (MD5) Previous issue date: 1982","Embargo set by: Seth Robbins for item 69400 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","60 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1982."]},{"key":"dc:title","label":"Title","values":["Hot Band Rotational Relaxation Time in Carbonyl Sulfide by Transient Infrared-Microwave Double Resonance"]}]}],"canonical_facts":{"dc:creator":["Leap, John William"],"dc:date":["2014-12-15T19:04:20Z","10000-01-01","1982"],"dc:description":["Rotational relaxation time (T) has been measured for pure Carbonyl Sulfide (('16)O('12)C('32)S) in a highly vibrationally and rotationally excited state (03('1f)0, J=24). A CO(,2) laser (P(,9)(24) line) was used to pulse excite the OCS gas: (01('1f)0, J=25) (--->) (03('1f)0, J=24). The resulting transient population difference between l doublet states, (03('1f)0, J=24) and 03('1e)0, J=24), was monitored with a microwave (7.4 GHz) probe signal. Individual transient infrared-microwave signals were analyzed and from the gain pulse shape it is concluded that population decay time (T(,1)) and polarization decay time (T(,2)) are approximately equal to a composite relaxation time (T). From the pressure dependence of T as pressure (p) changes from 0.04 to 0.3 Torr(5 to 40 Pa), it is concluded that (pT) = 32 ns(.)Torr = 4.3 (mu)s(.)Pa.","The CO(,2) laser included a transversely excited atmospheric pressure (TEA) gain section and a low pressure, selective, saturable absorber (NH(,3)) inside the laser cavity. The frequency shifted and modulated multimode pulse from the CO(,2) laser was abruptly truncated with a plasma shutter breakdown switch so that the OCS gas could be observed in the absence of further infrared excitation. The truncated laser pulse was used to transiently excite OCS gas in a 3-meter long arm of a WR90 waveguide bridge with pierced E plane bends. The microwave frequency was tuned to resonance with the l doublet transition and the bridge was adjusted to be sensitive to amplitude changes. Envelope detection of the amplified bridge imbalance yielded a video signal proportional to microwave gain. The signal to noise of individual transients was adequate and signal averaging was not used. Waveforms were recorded photographically from an oscilloscope. Values of relaxation time (T) were obtained from the transient gain pulse width by using a Bloch equation model for the gas and by considering the bandwidth limits of the video amplifiers.","Made available in DSpace on 2014-12-15T19:04:20Z (GMT). No. of bitstreams: 1 8218505.pdf: 1693638 bytes, checksum: 0d204a11b872e2bd9a76fbd3d632dce0 (MD5) Previous issue date: 1982","Embargo set by: Seth Robbins for item 69400 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","60 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1982."],"dc:identifier":["http://hdl.handle.net/2142/69234","(UMI)AAI8218505"],"dc:subject":["Engineering, Electronics and Electrical"],"dc:title":["Hot Band Rotational Relaxation Time in Carbonyl Sulfide by Transient Infrared-Microwave Double Resonance"],"dc:type":["text"],"thesis:degree_discipline":["Electrical Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:00Z"}