Atomic parameters for semi-empirical SCF-LCAO-MO calculations

The CNDO/BW modification of the C N D O /~ approximation was used within the PCILO framework. It was shown on some significant examples that all the good results of the original PCILO-CNDO/~ method can be reproduced by the modified version PCILO-CNDO/BW at least. Thus, preserving the quality of its results a computer-expense-reduced PCILO method is proposed for calculations on large molecular systems.

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“…and y X A are the atomic limits [21] (in a.u.) chosen to be consistent with the evaluation of the average one-center repulsion integral [22].…”

Section: Lochmann Weller and Kohlermentioning

confidence: 99%

A modified PCILO framework using the CNDO/Boyd–Whitehead parametrization

Lochmann

Weller

Köhler

1984

Int J of Quantum Chemistry

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“…With s l i e n l À 1 Ài e n l and e l i e n l À i e n l 1 we obtain The AO ionization energies s l and electron anities e l can be evaluated empirically from appropriate atomic spectral data; in this work, the AO parameters derived by Sichel and Whitehead are adopted [37]. The two-centre penetration terms u f ll in Eq.…”

Section: One-centre Termsmentioning

confidence: 99%

“…This expression involves the atomic parameters s l and e l that are taken from the tables of Sichel and Whitehead [37], and the two molecular penetration parameters d s and d p used in Eq. (14).…”

Section: One-centre Termsmentioning

confidence: 99%

The alternant hydrocarbon pairing theorem and all-valence electrons theory. An approximate LCOAO theory for the electronic absorption and MCD spectra of conjugated organic compounds, part 2

Spanget‐Larsen

1997

Theoretical Chemistry Accounts: Theory, Computation, and Modeli

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An approximate linear combination of orthogonalized atomic orbitals (LCOAO) all-valence electrons theory is described, based on a previously suggested partitioning of the Fock operator. Kinetic energy and penetration terms are evaluated explicitly in a LoÈ wdin OAO basis, while two-electron repulsion terms are treated according to the conventional neglect of dierential overlap (NDO) approximation. One-electron and penetration integrals are parameterized explicitly to predict approximate alternant pairing symmetry for the p-systems of benzene and napthalene. Application of the resulting LCOAO theory to a variety of alternant and non-alternant hydrocarbons demonstrates signi®cant improvements in the prediction of MCD B-terms and transition moment directions, particularly for alternant (4N+2)-or 4N-perimeter p-systems for which traditional NDO procedures fail.

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“…This method is particularly suitable for the present study since it is parameterized on diatomic and triatomic molecules to give the correct bond lengths and energy of a molecule. The core integrals, U,,, and the one-centre electron repulsion integrals 7AA, were taken from Sichel & Whitehead (1967). The two-centre electron repulsions were evaluated from the Ohno (1964) expression,…”

Section: (B) Cndo/bw Molecular-orbital Calculationsmentioning

confidence: 99%

A reinvestigation of the crystal and molecular structure of hexachloroborazine

Gopinathan¹,

Whitehead²,

Coulson³

et al. 1974

Acta Crystallogr B Struct Sci

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The intra-and intermolecular electrostatic interactions in hexachloroborazine are discussed, and are combined with CNDO/BW semi-empirical molecular-orbital calculations, and with the results of similar calculations on borazine and B-trichloroborazine to show that hexachloroborazine has a regular hexagonal ring structure. The X-ray diffraction analysis of Haasnoot, Verschoor, Romers & Groeneveld [Acta Cryst. (1972). B28, 2070-2073] indicated alternating B-N bond lengths. The X-ray diffraction data have been reinterpreted and shown to be consistent with a regular hexagonal ring structure for hexachloroborazine.

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Atomic parameters for semi-empirical SCF-LCAO-MO calculations

Cited by 171 publications

References 17 publications

A modified PCILO framework using the CNDO/Boyd–Whitehead parametrization

A modified PCILO framework using the CNDO/Boyd–Whitehead parametrization

The alternant hydrocarbon pairing theorem and all-valence electrons theory. An approximate LCOAO theory for the electronic absorption and MCD spectra of conjugated organic compounds, part 2

A reinvestigation of the crystal and molecular structure of hexachloroborazine

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