Generator Coordinate Hartree-Fock Method Research Articles

The generator coordinate Hartree-Fock method applied to the choice of a contracted gaussian basis for first-row atoms

The generator coordinate Hartree-Fock (GCHF) method is employed as a criterion for the selection of an 18s 12p gaussian basis for the atoms H, Li-Ne. The role of the weight functions in the assessment of the numerical integration range of the GCHF equations is shown. The extended basis is then contracted to [5s] (H) and [7s 5p] (Li-Ne) by a standard procedure and enriched with polarization functions. This basis is tested for H 2, BH, B 2, C 2, N 2, O 2, F 2, HF, LiF, BeO, BF, CN −, CO and NO +. The properties of interest were HF total energies, CISD bond distances and vibrational frequencies, and MP2 dissociation energies.

A method for the determination of the Hartree-Fock limit: application to closed-shell atoms

A procedure based on the discretized version of the generator coordinate Hartree-Fock method is introduced to reach the Hartree-Fock SCF limit. The method represents a simple and efficient operation to reach a high level of accuracy of electronic energy. Problems of linear dependence and local minima of energy are controlled. Results for some closed-shell atoms are presented.

Accurate universal Gaussian basis set for hydrogen through lanthanum generated with the generator coordinate Hartree-Fock method

The generator coordinate Hartree-Fock method is applied to generate an accurate universal Gaussian basis set for the atoms H ( Z = 1) through La ( Z = 57). The Hartree-Fock energy results obtained with our universal Gaussian basis set are compared with numerical Hartree-Fock results and with Hartree-Fock energy results obtained by using optimized Gaussian basis sets. For the atoms B through Ca we have obtained, when compared to the corresponding numerical Hartree-Fock results, an energy value within the accuracy of 10 −5–10 −4 E h, and for Sc through La this accuracy lies between 10 −4 and 10 −3 E h. The universal Gaussian basis set presented in this work is generated taking into account the sharing of exponential functions between all s, p and d atomic orbitals, i.e. the shell constraint.

Generator coordinate Hartree–Fock method applied to the choice of a contracted Gaussian basis for the second‐row atoms

Generator coordinate Hartree–Fock method applied to the choice of a contracted Gaussian basis for the second‐row atoms

Generator coordinate Hartree-Fock method applied to the choice of a contracted Gaussian basis for the second-row atoms

The generator coordinate Hartree–Fock (GCHF) method is employed as a criterion for the selection of a 18s12p Gaussian basis for the atoms Na–Ar. The role of the weight functions in the assessment of the numerical integration range of the GCHF equations is shown. The extended basis is then contracted to (10s6p) by a standard procedure and in combination with the previously contracted (7s5p) Gaussian basis for the atoms Li–Ne is enriched with polarization functions. This basis is tested for AlF, SiO, PN, BCl, and P2. The properties of interest were HF total energies, MP2 dipolar moments, bond distances, and dissociation energies. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 927–934, 1997

Gaussian- and Slater-type bases for ground and certain low-lying excited states of positive and negative ions of the atoms H through Xe based on the generator coordinate Hartree–Fock method

We applied a discretized version of the generator coordinate Hartree–Fock (GCHF) method to generate Gaussian- and Slater-type functions for mono positive and mono negative ions of the atoms H through Xe. The basis sizes for Slater-type functions are (12s, 10p, 10d) for positive ions, and (13s, 11p, 10d) for negative ions. In the case of Gaussian-type functions the bases are (18s, 12p, 11d) for both positive and negative species. Ground and excited state Hartree–Fock energies are calculated with these bases and the results compared with the best atom-optimized calculations and numerical HF results available. A discussion on the role of weight functions in the evaluation of electronic energies emphasizes the integral character of the GCHF method. Key words: Slater-type bases, Gaussian-type bases, generator coordinate Hartree–Fock, atomic ions.

Universal Gaussian and slater-type bases for atoms H to Xe based on the generator coordinate Hartree-Fock method

A previously generated (18s, 12p, 11d) universal Gaussian basis has been applied to the diatomic species H2, N2, BF, CO, HF, CH, P2, SiO, HF-, CH-, CH+ and BH+. The properties being calculated are total ground state Hartree-Fock and post-Hartree-Fock energies and harmonic vibrational frequencies. Comparison is made with values calculated in this work with standard bases, values from the literature and experiment. The performance of the universal basis is better or comparable to atom-optimized bases or numerical Hartree-Fock values.

The generator coordinate Hartree—Fock method for molecular systems. Near Hartree—Fock limit calculations for N 2, CO and BF

Generator coordinate Hartree—Fock calculations were performed for the fourteen-electron diatomic molecules N 2, CO and BF. The ground state HF energy and multipole electric moments were calculated. The Griffin—Wheeler HF equations were solved by discretization with the aid of the HONDO program. The Gaussian type basis was of size 26s18p10d7f for each atom. The results are of near numerical HF quality.

The generator coordinate Hartree-Fock method for molecular systems. Formalism and first applications to H 2, LiH and Li 2

The generator coordinate Hartree-Fock method is extended to molecular systems. The resulting equations are integrated numerically through discretization. The method is then implemented with the use of the GAUSSIAN 86 program and applied to the H 2, LiH and Li 2 diatomic species. The ground state Hartree-Fock energies (and dipole moment in the case of LiH) are calculated and compared with numerical Hartree-Fock values. The role of the molecular weight functions is discussed.

Generator coordinate gaussian expanded natural orbitals

An integral transform interpretation of natural orbitals is presented with the generator coordinate method as a background. Reference is made to the previously presented generator coordinate Hartree-Fock method. The technique for numerical integration is shown. Examples of continuous natural orbitals expanded in Gaussian atomic bases are presented for neutral and charged 2-4-electron atomic species. The calculations were implemented using the MELD codes.

Universal gaussian and Slater-type bases for atoms H to Xe based on the generator coordinate Hartree-Fock method

Application de la methode de Hartree Fock a coordonnees generatrices avec la technique de discretisation d'equations integrales, a l'obtention de bases universelles STO et GTO de haute qualite pour les atomes de H a Xe. Obtention de bases de types Slater (12s,10p,10d) et de Gaussien (18s,12p,11d). Mise en evidence du role des fonctions de poids