{"id":{"repo_id":"rice","oai_identifier":"oai:repository.rice.edu:1911/19177"},"canonical_url":"https://search.dev.ndltd.org/etd/rice/oai:repository.rice.edu:1911/19177","repository":{"repo_id":"rice","name":"Rice University","base_url":"https://repository.rice.edu/server/oai/request"},"display":{"title":"Molecular beam studies of excitation and electron transfer reactions","abstract":"Two studies were performed using crossed molecular beams. The first system studied was the reaction $\\rm Na\\sp* + KBr \\to NaBr + K\\sp*,$ determining how fine structure is transmitted through a reactive collision. Each fine structure state of Na$\\sp*(3\\sp2$P) is separately laser excited, and the fluorescence from the two fine structure states of K$\\sp*(4\\sp2$P) are separately monitored. The observed K* fine-structure state distributions were not simply statistical. While the product K* fine-structure states were statistically populated for excitation to Na$\\rm\\sp*(P\\sb{1/2}),$ they were not for excitation to Na$\\rm\\sp*(P\\sb{3/2}).$ These distributions were interpreted in terms of nonadiabatic interaction along different regions of the KBrNa molecular potential energy surfaces. These nonadiabatic interactions were also used to help explain the differing fine-structure state populations produced in the previous NaBr + K transition state spectra. A hyperthermal seeded supersonic alkali atom source was designed and constructed for use in collisional ionization experiments. The intensity of the new source was found to be ${\\approx}10\\sp5$ greater than the previous charge exchange source in the energy range of interest. This source was then used to determine preliminary appearance thresholds for collisional ionization between potassium and rubidium atoms and some molecules. From the thresholds, electron affinities for SF$\\sb6$ and CF$\\sb3$Br and the bond dissociation energy for the CH$\\sb3$Br bond could be obtained. These values were in good agreement with the literature values, although the electron affinity for CF$\\sb3$Br was slightly higher (1.06 $\\pm$ 0.10 eV) than the previous result in the literature (0.91 $\\pm$ 0.20 eV). The effect of electronic excitation of the alkali atom on collisional ionization was also explored. The cross section for the reaction of excited state $\\rm Rb\\sp* + SF\\sb6$ appears to be less than that for the ground state reaction. This reduction in cross section suggests that the excited state crossing can be considered to be nearly completely nonadiabatic for the experimental conditions. This result was reproduced in Landau-Zener calculations of the nonadiabatic probabilities and the ratio of the cross sections.","abstract_html":"Two studies were performed using crossed molecular beams. The first system studied was the reaction $\\rm Na\\sp* + KBr \\to NaBr + K\\sp*,$ determining how fine structure is transmitted through a reactive collision. Each fine structure state of Na$\\sp*(3\\sp2$P) is separately laser excited, and the fluorescence from the two fine structure states of K$\\sp*(4\\sp2$P) are separately monitored. The observed K* fine-structure state distributions were not simply statistical. While the product K* fine-structure states were statistically populated for excitation to Na$\\rm\\sp*(P\\sb{1/2}),$ they were not for excitation to Na$\\rm\\sp*(P\\sb{3/2}).$ These distributions were interpreted in terms of nonadiabatic interaction along different regions of the KBrNa molecular potential energy surfaces. These nonadiabatic interactions were also used to help explain the differing fine-structure state populations produced in the previous NaBr + K transition state spectra. A hyperthermal seeded supersonic alkali atom source was designed and constructed for use in collisional ionization experiments. The intensity of the new source was found to be ${\\approx}10\\sp5$ greater than the previous charge exchange source in the energy range of interest. This source was then used to determine preliminary appearance thresholds for collisional ionization between potassium and rubidium atoms and some molecules. From the thresholds, electron affinities for SF$\\sb6$ and CF$\\sb3$Br and the bond dissociation energy for the CH$\\sb3$Br bond could be obtained. These values were in good agreement with the literature values, although the electron affinity for CF$\\sb3$Br was slightly higher (1.06 $\\pm$ 0.10 eV) than the previous result in the literature (0.91 $\\pm$ 0.20 eV). The effect of electronic excitation of the alkali atom on collisional ionization was also explored. The cross section for the reaction of excited state $\\rm Rb\\sp* + SF\\sb6$ appears to be less than that for the ground state reaction. This reduction in cross section suggests that the excited state crossing can be considered to be nearly completely nonadiabatic for the experimental conditions. This result was reproduced in Landau-Zener calculations of the nonadiabatic probabilities and the ratio of the cross sections.","abstract_has_math":true,"creators":["Lewis, Lawrence Lyle"],"institution":"Rice University","degree_name":"Doctor of Philosophy","degree_level":"Doctoral","degree_discipline":"Natural Sciences","degree_department":null,"school":null,"contributors":[],"advisors":["Brooks, Philip R."],"committee_chairs":[],"committee_members":[],"year":1997,"date_issued":"1997","date_published":"1997","updated_at":"2026-07-24T04:10:24Z","subjects":["Physical chemistry"],"languages":["eng"],"rights":["Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/1911/19177","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Brooks, Philip R."]},{"key":"dc:creator","label":"Author","values":["Lewis, Lawrence Lyle"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2009-06-04T06:37:51Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2009-06-04T06:37:51Z"]},{"key":"dc:date.issued","label":"Date","values":["1997"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Natural Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Rice University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Physical chemistry"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/1911/19177"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Two studies were performed using crossed molecular beams. The first system studied was the reaction $\\rm Na\\sp* + KBr \\to NaBr + K\\sp*,$ determining how fine structure is transmitted through a reactive collision. Each fine structure state of Na$\\sp*(3\\sp2$P) is separately laser excited, and the fluorescence from the two fine structure states of K$\\sp*(4\\sp2$P) are separately monitored. The observed K* fine-structure state distributions were not simply statistical. While the product K* fine-structure states were statistically populated for excitation to Na$\\rm\\sp*(P\\sb{1/2}),$ they were not for excitation to Na$\\rm\\sp*(P\\sb{3/2}).$ These distributions were interpreted in terms of nonadiabatic interaction along different regions of the KBrNa molecular potential energy surfaces. These nonadiabatic interactions were also used to help explain the differing fine-structure state populations produced in the previous NaBr + K transition state spectra. A hyperthermal seeded supersonic alkali atom source was designed and constructed for use in collisional ionization experiments. The intensity of the new source was found to be ${\\approx}10\\sp5$ greater than the previous charge exchange source in the energy range of interest. This source was then used to determine preliminary appearance thresholds for collisional ionization between potassium and rubidium atoms and some molecules. From the thresholds, electron affinities for SF$\\sb6$ and CF$\\sb3$Br and the bond dissociation energy for the CH$\\sb3$Br bond could be obtained. These values were in good agreement with the literature values, although the electron affinity for CF$\\sb3$Br was slightly higher (1.06 $\\pm$ 0.10 eV) than the previous result in the literature (0.91 $\\pm$ 0.20 eV). The effect of electronic excitation of the alkali atom on collisional ionization was also explored. The cross section for the reaction of excited state $\\rm Rb\\sp* + SF\\sb6$ appears to be less than that for the ground state reaction. This reduction in cross section suggests that the excited state crossing can be considered to be nearly completely nonadiabatic for the experimental conditions. This result was reproduced in Landau-Zener calculations of the nonadiabatic probabilities and the ratio of the cross sections."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Molecular beam studies of excitation and electron transfer reactions"]}]}],"canonical_facts":{"dc:contributor.advisor":["Brooks, Philip R."],"dc:creator":["Lewis, Lawrence Lyle"],"dc:date.accessioned":["2009-06-04T06:37:51Z"],"dc:date.available":["2009-06-04T06:37:51Z"],"dc:date.issued":["1997"],"dc:description.abstract":["Two studies were performed using crossed molecular beams. The first system studied was the reaction $\\rm Na\\sp* + KBr \\to NaBr + K\\sp*,$ determining how fine structure is transmitted through a reactive collision. Each fine structure state of Na$\\sp*(3\\sp2$P) is separately laser excited, and the fluorescence from the two fine structure states of K$\\sp*(4\\sp2$P) are separately monitored. The observed K* fine-structure state distributions were not simply statistical. While the product K* fine-structure states were statistically populated for excitation to Na$\\rm\\sp*(P\\sb{1/2}),$ they were not for excitation to Na$\\rm\\sp*(P\\sb{3/2}).$ These distributions were interpreted in terms of nonadiabatic interaction along different regions of the KBrNa molecular potential energy surfaces. These nonadiabatic interactions were also used to help explain the differing fine-structure state populations produced in the previous NaBr + K transition state spectra. A hyperthermal seeded supersonic alkali atom source was designed and constructed for use in collisional ionization experiments. The intensity of the new source was found to be ${\\approx}10\\sp5$ greater than the previous charge exchange source in the energy range of interest. This source was then used to determine preliminary appearance thresholds for collisional ionization between potassium and rubidium atoms and some molecules. From the thresholds, electron affinities for SF$\\sb6$ and CF$\\sb3$Br and the bond dissociation energy for the CH$\\sb3$Br bond could be obtained. These values were in good agreement with the literature values, although the electron affinity for CF$\\sb3$Br was slightly higher (1.06 $\\pm$ 0.10 eV) than the previous result in the literature (0.91 $\\pm$ 0.20 eV). The effect of electronic excitation of the alkali atom on collisional ionization was also explored. The cross section for the reaction of excited state $\\rm Rb\\sp* + SF\\sb6$ appears to be less than that for the ground state reaction. This reduction in cross section suggests that the excited state crossing can be considered to be nearly completely nonadiabatic for the experimental conditions. This result was reproduced in Landau-Zener calculations of the nonadiabatic probabilities and the ratio of the cross sections."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["https://hdl.handle.net/1911/19177"],"dc:language.iso":["eng"],"dc:rights":["Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder."],"dc:subject":["Physical chemistry"],"dc:title":["Molecular beam studies of excitation and electron transfer reactions"],"dc:type":["Thesis"],"thesis:degree_discipline":["Natural Sciences"],"thesis:degree_level":["Doctoral"],"thesis:degree_name":["Doctor of Philosophy"],"thesis:institution_name":["Rice University"]},"updated_at":"2026-07-24T04:10:24Z"}