Zobrazeno 1 - 10
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pro vyhledávání: '"Paul Westhaus"'
Autor:
Paul Westhaus
Publikováno v:
International Journal of Quantum Chemistry. 16:215-223
We report calculations on the electronic states of ethylene using the canonical transformation cluster expansion formalism to generate an effective valence shell Hamiltonian. The approximate formulas are very sensitive to the partition of one-electro
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https://explore.openaire.eu/search/publication?articleId=doi_________::301d5c04cff16004bdebbc352701ffbe
https://doi.org/10.1002/qua.560160824
https://doi.org/10.1002/qua.560160824
Autor:
Paul Westhaus, Edward G. Bradford
Publikováno v:
International Journal of Quantum Chemistry. 10:231-236
The salient points of applying the canonical transformation-cluster expansion formalism to the problem of generating effective valence-shell Hamiltonians are reviewed. Substantial reduction in the strength of the two-body interaction is found to be i
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https://explore.openaire.eu/search/publication?articleId=doi_________::26ca5d9ba6f6a2c410f576201d8d090e
https://doi.org/10.1002/qua.560100723
https://doi.org/10.1002/qua.560100723
Autor:
Paul Westhaus
Publikováno v:
International Journal of Quantum Chemistry. 7:463-477
The Van Kampen cluster expansion method is adapted to the problem of resuming the commutator expansion arising in a canonical transformation upon the Hamiltonian operator of a many-electron system. The canonical transformation generates effective int
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https://explore.openaire.eu/search/publication?articleId=doi_________::f85e201ad7922437d03030ac71ab4353
https://doi.org/10.1002/qua.560070754
https://doi.org/10.1002/qua.560070754
Autor:
Oktay Sinanoǧlu, Paul Westhaus
Publikováno v:
International Journal of Quantum Chemistry. 4:391-411
A rigorous derivation of many-electron correlation functions for constructing the exact wave function for open shell molecules is given. These correlation functions are formally projections from the exact many-particle wave function and as such are p
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https://explore.openaire.eu/search/publication?articleId=doi_________::843272361df9786e109c7a7fda2cbbe1
https://doi.org/10.1002/qua.560040707
https://doi.org/10.1002/qua.560040707
Autor:
Paul Westhaus
Publikováno v:
International Journal of Quantum Chemistry. 21:617-632
We continue to examine the connection between perturbation theory and the Van Vleck unitary transformation. Here we illustrate the formalism derived earlier by applying it to compute the stationary states of the perturbed harmonic oscillator. We find
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https://explore.openaire.eu/search/publication?articleId=doi_________::189b3d49d2473b45678e4ff8fd5b7491
https://doi.org/10.1002/qua.560210309
https://doi.org/10.1002/qua.560210309
Autor:
Paul Westhaus
Publikováno v:
The Journal of Chemical Physics. 78:6833-6840
We present a generalization of the density functional formalism based upon constrained variations of the expectation value E=〈Ψ‖H‖Ψ〉. The essential idea is to find the minimum value of E with respect to a set of state vectors Sa={‖Ψ〉a}
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https://doi.org/10.1063/1.444629
https://doi.org/10.1063/1.444629
Publikováno v:
The Journal of Chemical Physics. 62:1607-1622
We construct an effective Hamiltonian for the valence shell of a large electronic system. The procedure begins by classifying the complete one electron space according to core, valence, and excited orbitals. An N−electron subspace TN spanned by Sla
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https://explore.openaire.eu/search/publication?articleId=doi_________::b3b0c85c209f4e27c5af3cccee4bf584
https://doi.org/10.1063/1.430712
https://doi.org/10.1063/1.430712
Autor:
Paul Westhaus
Publikováno v:
The Journal of Chemical Physics. 73:5197-5203
We extend the formal apparatus for generating effective electronic Hamiltonians by a unitary (canonical) transformation on the Coulomb Hamiltonian to model spaces having various numbers of valence electrons. This formal structure is then used to anal
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https://explore.openaire.eu/search/publication?articleId=doi_________::36ad7528cc6dedf2fe6e7767e622beca
https://doi.org/10.1063/1.439947
https://doi.org/10.1063/1.439947
Autor:
Paul Westhaus, Edward G. Bradford
Publikováno v:
The Journal of Chemical Physics. 63:5416-5427
We present the first numerical results of the canonical tranformation formalism for generating the valence shell effective interactions. Considering the valence space to be formed as the antisymmetrized direct product of 2s and 2p type orbitals we ha
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https://doi.org/10.1063/1.431348
https://doi.org/10.1063/1.431348
Autor:
Paul Westhaus
Publikováno v:
International Journal of Quantum Chemistry. 20:1243-1253
The connections between open shell Brillouin–Wigner perturbation theory and the Van Vleck unitary transformation formalisms for generating effective Hamiltonians are explored. An explicit expression is obtained relating the generator Ŝ of the unit
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::e45e3cc6d43f30f715501daa320eaa9a
https://doi.org/10.1002/qua.560200609
https://doi.org/10.1002/qua.560200609