{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/70194"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/70194","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Electron Correlation Studies of Weakly Bonded Systems","abstract":"Spin-adapted Coupled Cluster Double Substitution (CCD) theory is developed and the matrix operators of Pair Operator Formalism are derived. The set of equations for the CCD coefficients is related to a full variational solution of the CCD wavefunction. An approximation to CCD theory (ACCD) is developed and compared to the CEPA approximations. The SCEP, CEPA, and CCD potential energy curves of the closed shell dimers of the homo-nuclear series He(,2), Be(,2), and Mg(,2) and the hetero-nuclear series HeBe, HeMg, BeMg are reported. The SCEP and CCD curves are similar suggesting that the size-consistency error is of minor importance. The CEPA-0 potential curves of the Be dimers have deep, close-in wells while the SCEP and CCD potential curves have shallower wells. SCEP and CEPA-2 calculations are also reported for Mg(,4). The Mg(,4) species is found to be chemically bonded due to the correlation effects of the d orbitals.","abstract_html":"Spin-adapted Coupled Cluster Double Substitution (CCD) theory is developed and the matrix operators of Pair Operator Formalism are derived. The set of equations for the CCD coefficients is related to a full variational solution of the CCD wavefunction. An approximation to CCD theory (ACCD) is developed and compared to the CEPA approximations. The SCEP, CEPA, and CCD potential energy curves of the closed shell dimers of the homo-nuclear series He(,2), Be(,2), and Mg(,2) and the hetero-nuclear series HeBe, HeMg, BeMg are reported. The SCEP and CCD curves are similar suggesting that the size-consistency error is of minor importance. The CEPA-0 potential curves of the Be dimers have deep, close-in wells while the SCEP and CCD potential curves have shallower wells. SCEP and CEPA-2 calculations are also reported for Mg(,4). The Mg(,4) species is found to be chemically bonded due to the correlation effects of the d orbitals.","abstract_has_math":false,"creators":["Chiles, Richard Andrew"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Chemistry","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-15T23:17:43Z","date_published":"2014-12-15T23:17:43Z","updated_at":"2026-07-22T22:26:02Z","subjects":["Chemistry, Physical"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8302831"],"render_values":[{"text":"(UMI)AAI8302831","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/70194","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Chiles, Richard Andrew"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-15T23:17:43Z","10000-01-01","1982"]},{"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":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/70194","(UMI)AAI8302831"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Spin-adapted Coupled Cluster Double Substitution (CCD) theory is developed and the matrix operators of Pair Operator Formalism are derived. The set of equations for the CCD coefficients is related to a full variational solution of the CCD wavefunction. An approximation to CCD theory (ACCD) is developed and compared to the CEPA approximations. The SCEP, CEPA, and CCD potential energy curves of the closed shell dimers of the homo-nuclear series He(,2), Be(,2), and Mg(,2) and the hetero-nuclear series HeBe, HeMg, BeMg are reported. The SCEP and CCD curves are similar suggesting that the size-consistency error is of minor importance. The CEPA-0 potential curves of the Be dimers have deep, close-in wells while the SCEP and CCD potential curves have shallower wells. SCEP and CEPA-2 calculations are also reported for Mg(,4). The Mg(,4) species is found to be chemically bonded due to the correlation effects of the d orbitals.","Made available in DSpace on 2014-12-15T23:17:43Z (GMT). No. of bitstreams: 1 8302831.pdf: 1836832 bytes, checksum: 41ec94a4c97fb617ed2d29836452b8ee (MD5) Previous issue date: 1982","Embargo set by: Seth Robbins for item 70360 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","83 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1982."]},{"key":"dc:title","label":"Title","values":["Electron Correlation Studies of Weakly Bonded Systems"]}]}],"canonical_facts":{"dc:creator":["Chiles, Richard Andrew"],"dc:date":["2014-12-15T23:17:43Z","10000-01-01","1982"],"dc:description":["Spin-adapted Coupled Cluster Double Substitution (CCD) theory is developed and the matrix operators of Pair Operator Formalism are derived. The set of equations for the CCD coefficients is related to a full variational solution of the CCD wavefunction. An approximation to CCD theory (ACCD) is developed and compared to the CEPA approximations. The SCEP, CEPA, and CCD potential energy curves of the closed shell dimers of the homo-nuclear series He(,2), Be(,2), and Mg(,2) and the hetero-nuclear series HeBe, HeMg, BeMg are reported. The SCEP and CCD curves are similar suggesting that the size-consistency error is of minor importance. The CEPA-0 potential curves of the Be dimers have deep, close-in wells while the SCEP and CCD potential curves have shallower wells. SCEP and CEPA-2 calculations are also reported for Mg(,4). The Mg(,4) species is found to be chemically bonded due to the correlation effects of the d orbitals.","Made available in DSpace on 2014-12-15T23:17:43Z (GMT). No. of bitstreams: 1 8302831.pdf: 1836832 bytes, checksum: 41ec94a4c97fb617ed2d29836452b8ee (MD5) Previous issue date: 1982","Embargo set by: Seth Robbins for item 70360 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","83 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1982."],"dc:identifier":["http://hdl.handle.net/2142/70194","(UMI)AAI8302831"],"dc:subject":["Chemistry, Physical"],"dc:title":["Electron Correlation Studies of Weakly Bonded Systems"],"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":"2026-07-22T22:26:02Z"}