The study of electron impact single ionization of atoms and molecules has provided valuable information about fundamental collisions. The most detailed information is obtained from triple differential cross sections (TDCS) in which the energy and momentum of all three final state particles are determined. These cross sections are much more difficult for theory since the detailed kinematics of the experiment become important. There are many theoretical approximations for ionization of molecules. One of the successful methods is the molecular 3-body distorted wave (M3DW) approximation. One of the strengths of the DW approximation is that it can be applied for any energy and any size molecule.
One of the approximations that has been made to significantly reduce the required computer time is the OAMO (orientation averaged molecular orbital) approximation. In this dissertation, the accuracy of the M3DW-OAMO is tested for different molecules. Surprisingly, the M3DW-OAMO approximation yields reasonably good agreement with experiment for ionization of H2 and N2. On the other hand, the M3DW-OAMO results for ionization of CH4, NH3 and DNA derivative molecules did not agree very well with experiment. Consequently, we proposed the M3DW with a proper average (PA) calculation.
In this dissertation, it is shown that the M3DW-PA calculations for CH4 and SF6 are in much better agreement with experimental data than the M3DW-OAMO results.
\"--Abstract, page iii.","abstract_html":"<p>The study of electron impact single ionization of atoms and molecules has provided valuable information about fundamental collisions. The most detailed information is obtained from triple differential cross sections (TDCS) in which the energy and momentum of all three final state particles are determined. These cross sections are much more difficult for theory since the detailed kinematics of the experiment become important. There are many theoretical approximations for ionization of molecules. One of the successful methods is the molecular 3-body distorted wave (M3DW) approximation. One of the strengths of the DW approximation is that it can be applied for any energy and any size molecule.</p><p>One of the approximations that has been made to significantly reduce the required computer time is the OAMO (orientation averaged molecular orbital) approximation. In this dissertation, the accuracy of the M3DW-OAMO is tested for different molecules. Surprisingly, the M3DW-OAMO approximation yields reasonably good agreement with experiment for ionization of H<sub>2</sub> and N<sub>2</sub>. On the other hand, the M3DW-OAMO results for ionization of CH<sub>4</sub>, NH<sub>3</sub> and DNA derivative molecules did not agree very well with experiment. Consequently, we proposed the M3DW with a proper average (PA) calculation.</p><p>In this dissertation, it is shown that the M3DW-PA calculations for CH<sub>4</sub> and SF<sub>6</sub> are in much better agreement with experimental data than the M3DW-OAMO results.</p>"--Abstract, page iii.</p>","abstract_has_math":false,"creators":["Chaluvadi, Hari"],"institution":"Missouri University of Science and Technology","degree_name":"Ph. D. in Physics","degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016-02-10T08:00:00Z","date_published":"2016-02-10T08:00:00Z","updated_at":"2026-07-24T03:19:54Z","subjects":["Molecular 3-body distorted wave","Proper average","Scattering","Triple differential cross sections","Physics"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarsmine.mst.edu/doctoral_dissertations/2405","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Chaluvadi, Hari"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2016-02-10T08:00:00Z"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation - Open Access"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph. D. in Physics"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Missouri University of Science and Technology"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Molecular 3-body distorted wave","Proper average","Scattering","Triple differential cross sections","Physics"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarsmine.mst.edu/doctoral_dissertations/2405"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The study of electron impact single ionization of atoms and molecules has provided valuable information about fundamental collisions. The most detailed information is obtained from triple differential cross sections (TDCS) in which the energy and momentum of all three final state particles are determined. These cross sections are much more difficult for theory since the detailed kinematics of the experiment become important. There are many theoretical approximations for ionization of molecules. One of the successful methods is the molecular 3-body distorted wave (M3DW) approximation. One of the strengths of the DW approximation is that it can be applied for any energy and any size molecule.
One of the approximations that has been made to significantly reduce the required computer time is the OAMO (orientation averaged molecular orbital) approximation. In this dissertation, the accuracy of the M3DW-OAMO is tested for different molecules. Surprisingly, the M3DW-OAMO approximation yields reasonably good agreement with experiment for ionization of H2 and N2. On the other hand, the M3DW-OAMO results for ionization of CH4, NH3 and DNA derivative molecules did not agree very well with experiment. Consequently, we proposed the M3DW with a proper average (PA) calculation.
In this dissertation, it is shown that the M3DW-PA calculations for CH4 and SF6 are in much better agreement with experimental data than the M3DW-OAMO results.
\"--Abstract, page iii."]},{"key":"dc:title","label":"Title","values":["Accuracy of theory for calculating electron impact ionization of molecules"]}]}],"canonical_facts":{"dc:creator":["Chaluvadi, Hari"],"dc:date.available":["2016-02-10T08:00:00Z"],"dc:description.abstract":["The study of electron impact single ionization of atoms and molecules has provided valuable information about fundamental collisions. The most detailed information is obtained from triple differential cross sections (TDCS) in which the energy and momentum of all three final state particles are determined. These cross sections are much more difficult for theory since the detailed kinematics of the experiment become important. There are many theoretical approximations for ionization of molecules. One of the successful methods is the molecular 3-body distorted wave (M3DW) approximation. One of the strengths of the DW approximation is that it can be applied for any energy and any size molecule.
One of the approximations that has been made to significantly reduce the required computer time is the OAMO (orientation averaged molecular orbital) approximation. In this dissertation, the accuracy of the M3DW-OAMO is tested for different molecules. Surprisingly, the M3DW-OAMO approximation yields reasonably good agreement with experiment for ionization of H2 and N2. On the other hand, the M3DW-OAMO results for ionization of CH4, NH3 and DNA derivative molecules did not agree very well with experiment. Consequently, we proposed the M3DW with a proper average (PA) calculation.
In this dissertation, it is shown that the M3DW-PA calculations for CH4 and SF6 are in much better agreement with experimental data than the M3DW-OAMO results.
\"--Abstract, page iii."],"dc:identifier":["https://scholarsmine.mst.edu/doctoral_dissertations/2405"],"dc:subject":["Molecular 3-body distorted wave","Proper average","Scattering","Triple differential cross sections","Physics"],"dc:title":["Accuracy of theory for calculating electron impact ionization of molecules"],"dc:type":["Dissertation - Open Access"],"thesis:degree_name":["Ph. D. in Physics"],"thesis:institution_name":["Missouri University of Science and Technology"]},"updated_at":"2026-07-24T03:19:54Z"}