[
    {
        "id": "authors:cvpr8-hxn15",
        "collection": "authors",
        "collection_id": "cvpr8-hxn15",
        "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180406-080326206",
        "type": "book_section",
        "title": "Parallel Calculation of Electron-Transfer and Resonance Matrix Elements of Hartree-Fock and Generalized Valence Bond Wave Functions",
        "book_title": "Parallel Computing in Computational Chemistry",
        "author": [
            {
                "family_name": "Bierwagen",
                "given_name": "Erik P.",
                "clpid": "Bierwagen-E-P"
            },
            {
                "family_name": "Coley",
                "given_name": "Terry R.",
                "clpid": "Coley-T-R"
            },
            {
                "family_name": "Goddard",
                "given_name": "William A., III",
                "orcid": "0000-0003-0097-5716",
                "clpid": "Goddard-W-A-III"
            }
        ],
        "abstract": "We review the theory for the computation of the Hamiltonian matrix element between two distinct electronic wave functions \u03c8_A and \u03c8_B sharing the same nuclear configuration but differing electronic density distributions. For example, \u03c8_A and \u03c8_B might describe two endpoints in an electron transfer reaction or two configurations in a resonance description of a molecule. In such cases the calculation of the rate of electron transfer or resonance energy requires evaluation of <\u03c8_A\\\u0124\\\u03c8_B> = H_(AB) matrix elements. Because the orbitals of \u03c8_A and \u03c8_B have complicated (non-orthogonal) relationships, the calculation of H_(AB) had been computationally intensive. In this paper we consider \u03c8_A, \u03c8_B having the form of closed or open-shell Hartree-Fock or Generalized Valence Bond wave functions and show the parallel structure of the theory. Using this parallel structure we present an efficient computational implementation for shared memory multiprocessors.",
        "doi": "10.1021/bk-1995-0592.ch007",
        "isbn": "9780841231665",
        "publisher": "American Chemical Society",
        "place_of_publication": "Washington, DC",
        "publication_date": "1995-05-17",
        "pages": "84-96"
    },
    {
        "id": "authors:dmwh6-g0506",
        "collection": "authors",
        "collection_id": "dmwh6-g0506",
        "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180529-145628341",
        "type": "article",
        "title": "Theoretical Studies of Ziegler-Natta Catalysis: Structural Variations and Tacticity Control",
        "author": [
            {
                "family_name": "Bierwagen",
                "given_name": "Erik P.",
                "clpid": "Bierwagen-E-P"
            },
            {
                "family_name": "Bercaw",
                "given_name": "John E.",
                "clpid": "Bercaw-J-E"
            },
            {
                "family_name": "Goddard",
                "given_name": "W. A., III",
                "orcid": "0000-0003-0097-5716",
                "clpid": "Goddard-W-A-III"
            }
        ],
        "abstract": "Models for the likely active catalysts in homogeneous Ziegler-Natta systems have been studied using ab initio quantum chemical methods. We investigated the geometries of the isoelectronic model complexes, X_2M-R where X = Cl or Cp = (\u03b7^5-C_5H_5); where M = Sc and Ti^+ (and also Ti); and where R = H, CH_3, or SiH_3. The general trend is that the M = Sc compounds strongly prefer a planar configuration, whereas the M = Ti^+ cases generally prefer pyramidal geometries. This difference in geometry can be related to the differing ground-state electronic configurations for the metals: Sc is (4s)^2(3d)^1, whereas Ti^+ is (4s)^1(3d)^2. The nonplanar geometry for [Cp_2Ti-R]^+ suggests an explanation for the origin of stereospecificity in the syndiotactic polymerization by unsymmetric metallocene catalysts. These results suggest that {(\u03b7^5-C_5H_4)CMe_2(\u03b7^5-fluorenyl)}Sc-R would not catalyze syndiotactic polymerization under these conditions.",
        "doi": "10.1021/ja00083a037",
        "issn": "0002-7863",
        "publisher": "American Chemical Society",
        "publication": "Journal of the American Chemical Society",
        "publication_date": "1994-02-23",
        "series_number": "4",
        "volume": "116",
        "issue": "4",
        "pages": "1481-1489"
    }
]