| Strongly contracted canonical transformation theory. | |
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MedLine Citation:
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PMID: 20095662 Owner: NLM Status: PubMed-not-MEDLINE |
Abstract/OtherAbstract:
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Canonical transformation (CT) theory describes dynamic correlation in multireference systems with large active spaces. Here we discuss CT theory's intruder state problem and why our previous approach of overlap matrix truncation becomes infeasible for sufficiently large active spaces. We propose the use of strongly and weakly contracted excitation operators as alternatives for dealing with intruder states in CT theory. The performance of these operators is evaluated for the H(2)O, N(2), and NiO molecules, with comparisons made to complete active space second order perturbation theory and Davidson-corrected multireference configuration interaction theory. Finally, using a combination of strongly contracted CT theory and orbital-optimized density matrix renormalization group theory, we evaluate the singlet-triplet gap of free base porphin using an active space containing all 24 out-of-plane 2p orbitals. Modeling dynamic correlation with an active space of this size is currently only possible using CT theory. |
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Authors:
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Eric Neuscamman; Takeshi Yanai; Garnet Kin-Lic Chan |
Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: The Journal of chemical physics Volume: 132 ISSN: 1089-7690 ISO Abbreviation: J Chem Phys Publication Date: 2010 Jan |
Date Detail:
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Created Date: 2010-01-25 Completed Date: 2010-03-25 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0375360 Medline TA: J Chem Phys Country: United States |
Other Details:
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Languages: eng Pagination: 024106 Citation Subset: - |
Affiliation:
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Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA. eric.neuscamman@gmail.com |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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