Topic
Zero differential overlap
About: Zero differential overlap is a research topic. Over the lifetime, 254 publications have been published within this topic receiving 8648 citations.
Papers published on a yearly basis
1 / 2
Papers
TL;DR: In this article, the theory of electronic spectra and electronic structure was further developed and applied to ethylene, butadiene, benzene, pyridine, pyrimidine, pyrazine, and s-triazine.
Abstract: The theory of electronic spectra and electronic structure, the elucidation of which was begun in the first paper of this series, is further developed and applied to ethylene, butadiene, benzene, pyridine, pyrimidine, pyrazine, and s‐triazine.A realistic and consistent LCAO‐MO π‐electron theory should allow the σ‐electrons to adjust themselves to the instantaneous positions of the mobile π‐electrons. This is accomplished in the theory by assignment of empirical values to the Coulomb electronic repulsion integrals and Coulomb penetration integrals which enter the formulas, these values being obtained in a prescribed way from valence state ionization potentials and electron affinities of atoms. Use of the empirical values in the molecular orbital theory reduces the magnitude of computed singlet‐triplet splittings and the effects of configuration interaction without complicating the mathematics. From the valence‐bond point of view, ionic structures may be said to be enhanced.The applications to hydrocarbons a...
1,695 citations
TL;DR: In this article, a method for computing electronic molecular energy up to the third-order in perturbation theory using fully localized bond orbitals with zero differential overlap between them is presented.
Abstract: Formulas are given allowing the calculation of electronic molecular energy up to the third-order in a perturbation theory using fully localized bond orbitals with zero differential overlap between them. The method is applied to small molecules using the CNDO approximations of Pople and Segal.
374 citations
TL;DR: In the multiplicative integral approximation (MIA), two-electron integrals are evaluated using an expansion of a product of two Gaussians in terms of auxiliary functions as discussed by the authors.
Abstract: In the multiplicative integral approximation (MIA), two-electron integrals are evaluated using an expansion of a product of two Gaussians in terms of auxiliary functions. An estimator of the error introduced by the approximation is incorporated in the self-consistent field (SCF) calculations and the integrals for which the error estimate is larger than a preset value are systematically corrected. In this way the results of a MIA-assisted calculation have the same accuracy as a conventional calculation. The full exploitation of the expansion technique while constructing the Fock-matrix allows important time savings. Results are presented for a number of test cases.
265 citations
TL;DR: In this paper, a new approach based on partial retention of diatomic differential overlap over an orthogonalized basis is described for approximating LCAO SCF molecular orbital wavefunctions at the minimum basis set level for closed shells molecules containing hydrogen and first row atoms.
Abstract: A new approach, based on partial retention of diatomic differential overlap over an orthogonalized basis, is described for approximating LCAO SCF molecular orbital wavefunctions at the minimum basis set level for closed‐shell molecules containing hydrogen and first‐row atoms. The SCF equations are solved explicitly, retaining all one‐electron integrals and approximating two‐electron Coulomb integrals, hybrid integrals, and exchange integrals of the forms (iAjA | iAjA) and (iAjB | jAjB) for centers A and B. Single‐center averaging processes otherwise required for rotational invariance are avoided by the use of local atomic‐centered axes which are unique in anisotropic environments. The result is accuracy comparable to that of much more elaborate methods such as STO‐3G, in computing times only moderately longer than for simpler methods based on neglect of differential overlap such as CNDO and INDO. Both unparameterized and parameterized methods are reported. Comparison of parameterized results with ab initi...
199 citations
TL;DR: In this article, general recurrence formulas for various types of one-and two-electron molecular integrals over Cartesian Gaussian functions are derived by introducing basic integrals, which are capable of dealing with any spatial operators in the nonrelativistic forms of the relativistic wave equations, those with the kernel of the Fourier transform, and any order of their derivatives with respect to the function centers in the above integrals.
Abstract: General recurrence formulas for various types of one‐ and two‐electron molecular integrals over Cartesian Gaussian functions are derived by introducing basic integrals. These formulas are capable of dealing with (1) molecular integrals with any spatial operators in the nonrelativistic forms of the relativistic wave equations, (2) those with the kernel of the Fourier transform, (3) those with arbitrarily defined spatial operators so far as the integrals can be expressed in terms of the basic integrals, and (4) any order of their derivatives with respect to the function centers in the above integrals. Thus, the present formulation can cover a large class of molecular integrals necessary for theoretical studies of molecular systems by ab initio calculations, and furthermore provides us with an efficient scheme of computing them by virtue of its recursive nature.
146 citations
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Performance Metrics
| Year | Papers |
|---|---|
| 2017 | 2 |
| 2016 | 3 |
| 2015 | 1 |
| 2014 | 2 |
| 2013 | 3 |
| 2012 | 2 |