scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Gaussian‐Type Functions for Polyatomic Systems. II

01 Mar 1970-Journal of Chemical Physics (American Institute of Physics)-Vol. 42, Iss: 4, pp 1293-1302
TL;DR: In this article, the use of a linear combination of Gaussian type orbitals (CGTO) instead of an individual Gaussian-type orbital (GTO) as a unit of basis functions for large-scale molecular calculations is discussed.
Abstract: The use of a linear combination of Gaussian‐type orbitals (CGTO), instead of an individual Gaussian‐type orbital (GTO), as a unit of basis functions for large‐scale molecular calculations, is discussed. A systematic construction of the CGTO basis functions is attempted and the results for the atoms from Li through Ar are reported.
Citations
More filters
Journal ArticleDOI
TL;DR: In this paper, the effects of contraction on the energies and one-electron properties of the water and nitrogen molecules were investigated, and the authors obtained principles which can be used to predict optimal contraction schemes for other systems without the necessity of such exhaustive calculations.
Abstract: The contraction of Gaussian basis functions for use in molecular calculations is investigated by considering the effects of contraction on the energies and one‐electron properties of the water and nitrogen molecules. The emphasis is on obtaining principles which can be used to predict optimal contraction schemes for other systems without the necessity of such exhaustive calculations. Using these principles, contractions are predicted for the first‐row atoms.

4,595 citations

Journal ArticleDOI
TL;DR: In this article, a Gaussian basis set consisting of 14s-type, 9p-type and 5d-type functions has been optimized for the third row atoms up to Zn.
Abstract: A Gaussian basis set consisting of 14s‐type, 9p‐type, and 5d‐type functions has been optimized for the third‐row atoms up to Zn. Energy values are reported for different contractions of this basis set.

3,054 citations

Journal ArticleDOI
TL;DR: In this article, a contracted Gaussian basis set capable of describing about 63% of the correlation energy of N2 has been used in a detailed configuration-interaction calculation, and second-order perturbation theory overestimated the correlated energy by 23-50% depending on how H0 was chosen.
Abstract: A contracted Gaussian basis set capable of describing about 63% of the correlation energy of N2 has been used in a detailed configuration-interaction calculation. Second-order perturbation theory overestimated the correlation energy by 23–50% depending on how H0 was chosen. Pair-pair interaction affects the correlation energy by about 20% while quadruple excitations have an 8% effect.

2,374 citations

Journal ArticleDOI
TL;DR: Theoretical D determination of Electron Affinities and Statistical Analysis of DFT Results ThroughComparisons to Experiment and Other theoretical Methods and Specific Theoretical Successes 251E.
Abstract: I. Introduction and Scope 231A. Definitions of Atomic Electron Affinities 233B. Definitions of Molecular Electron Affinities 233II. Experimental Photoelectron Electron Affinities 235A. Historical Background 235B. The Photoeffect 236C. Experimental Methods 237D. Time-of-Flight Negative Ion PhotoelectronSpectroscopy239E. Some Thermochemical Uses of ElectronAffinities241F. Layout of Table 10: ExperimentalPhotoelectron Electron Affinities242III. Theoretical Determination of Electron Affinities 242A. Historical Background 2421. Theoretical Predictions of Atomic ElectronAffinities2422. Theoretical Predictions of MolecularElectron Affinities243B. Present Status of Theoretical Electron AffinityPredictions243C. Basis Sets and Theoretical Electron Affinities 244D. Density Functional Theory (DFT) andElectron Affinities245E. Layout of Tables 8 and 9: Theoretical DFTElectron Affinities247F. Details of Density Functional MethodsEmployed in Tables 8 and 9247IV. Discussion and Observations 248A. Statistical Analysis of DFT Results ThroughComparisons to Experiment and OtherTheoretical Methods248B. Theoretical EAs for Species with UnknownExperimental EAs251C. On the Applicability of DFT to Anions and theFuture of DFT EA Predictions251D. Specific Theoretical Successes 251E. Interesting Problems 2521. C

1,137 citations

Journal ArticleDOI
TL;DR: In this paper, the (14s11p5d) primitives basis set of Dunning for the third-row main group atoms Ga-Kr has been contracted (6s4p1d).
Abstract: The (14s11p5d) primitives basis set of Dunning for the third-row main group atoms Ga-Kr has been contracted (6s4p1d). The core functions have been relatively highly contracted while those which represent the valence region have been left uncontracted to maintain flexibility. Calculations with the (6s4p1d) contraction are reported for a variety of molecules involving third-row atoms. This basis set is found to satisfactorily reproduce experimental properties such as geometric configurations, dipole moments, and vibrational frequencies for a range of molecules. Comparisons are made with the performance of the uncontracted basis set. Polarization functions for the contracted basis set are reported and performance of the basis set with and without polarization functions is examined. A relaxation of the (6s4p1d) contraction to (9s6p2d) for higher level energy calculations is also presented.

1,005 citations

References
More filters
Book
01 Jan 1966

2,966 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that the only obstacle to the evaluation of wave functions of any required degree of accuracy is the labour of computation, and that all necessary integrals can be explicitly evaluated.
Abstract: This communication deals with the general theory of obtaining numerical electronic wave functions for the stationary states of atoms and molecules. It is shown that by taking Gaussian functions, and functions derived from these by differentiation with respect to the parameters, complete systems of functions can be constructed appropriate to any molecular problem, and that all the necessary integrals can be explicitly evaluated. These can be used in connexion with the molecular orbital method, or localized bond method, or the general method of treating linear combinations of many Slater determinants by the variational procedure. This general method of obtaining a sequence of solutions converging to the accurate solution is examined. It is shown that the only obstacle to the evaluation of wave functions of any required degree of accuracy is the labour of computation. A modification of the general method applicable to atoms is discussed and considered to be extremely practicable.

1,036 citations

Journal ArticleDOI
TL;DR: In this article, self-consistent field wavefunctions have been obtained for the ground states of the first row atoms and for the excited states belonging to the same configurations, without any additional approximations except for those inherent in the expansion method.
Abstract: Self-consistent field wavefunctions have been obtained for the ground states of the first row atoms and for the excited states belonging to the same configurations. They are the solution of the variational problem of finding the best orbitals for a given state, without any additional approximations except for those inherent in the expansion method.

212 citations

Journal ArticleDOI
TL;DR: In this article, the method of least squares is used to obtain approximate expansions of Slater-type orbitals in terms of Gaussian type orbitals, which are good enough to use in quantum mechenical calculations of molecules.
Abstract: The details of the method of least squares for obtaining approximate expansions of Slater-type orbitals in terms of Gaussian type orbitals are described. Such Gaussian expansions are given for the 1 s , 2 s , 2 p , 3 s , 3 p and 3 d Slater-type orbitals. These expansions will be good enough to use in the quantum mechenical calculations of molecules.

177 citations