Accurate universal basis set for H through Xe for Hartree–Fock calculations

Theoretical Chemistry Accounts: Theory, Computation, and Modeli

Centoducatte

Castro

2000

The improved generator coordinate Hartree± Fock (GCHF) method is extended to molecular systems. The Grin±Hill±Wheeler±HF equations were solved by an integral discretization technique. The method is then implemented with the use of the GAMESS program and applied to the H 2 , Li 2 , and LiH molecules. For these molecules, sequences of basis sets of atom-centred Gaussian-type functions are employed to explore the accuracy achieved with our approach. For all systems studied, our ground-state HF total energies are better than those obtained with basis sets generated with the original GCHF method for molecules and larger eventempered basis sets. For H 2 , Li 2 , and LiH, the dierences between our best energies and the corresponding numerical HF results are about 2´10 )2 , 1, and 4´10 )1 lhartree, respectively. The dipole, quadrupole, and octupole moments at the center of mass and electric ®eld, the electric ®eld gradient, the electrostatic potential, and the electron density at the nuclei were evaluated and compared with results reported in the literature.

Section: Introductionmentioning

confidence: 99%

Improved generator coordinate Hartree-Fock method for molecular systems: application to H 2 , Li 2 and LiH

Theoretical Chemistry Accounts: Theory, Computation, and Modeli

Centoducatte

Castro

2000

Accurate adapted Gaussian basis sets for the atoms from H through Xe

Muniz

1999

Int. J. Quant. Chem.

ABSTRACT:We have applied the generator coordinate Hartree᎐Fock method to generate adapted Gaussian basis sets for the atoms from H through Xe. The Griffin᎐Hill᎐Wheeler᎐Hartree᎐Fock equations are integrated numerically generating accurate basis sets for these atoms. Our atomic wave functions are an improvement over those of Clementi et al. using larger atom-optimized geometrical Gaussian basis sets and Jorge et al. using a universal Gaussian basis set. In all cases, the current wave functions predict total energy results within 6.13 = 10 y4 hartree of the numerical Hartree᎐Fock limit.

An improved generator coordinate Hartree-Fock method applied to the choice of contracted Gaussian basis sets for first-row diatomic molecules

Pinheiro

Castro

2000

Int. J. Quant. Chem.

Accurate Gaussian basis sets (18s for Li and Be and 20s11p for the atoms from B to Ne) for the first-row atoms, generated with an improved generator coordinate Hartree-Fock method, were contracted and enriched with polarization functions. These basis sets were tested for B 2 , C 2 , BeO, CN − , LiF, N 2 , CO, BF, NO + , O 2 , and F 2 . At the Hartree-Fock (HP), second-order Møller-Plesset (MP2), fourth-order Møller-Plesset (MP4), and density functional theory (DFT) levels, the dipole moments, bond lengths, and harmonic vibrational frequencies were studied, and at the MP2, MP4, and DFT levels, the dissociation energies were evaluated and compared with the corresponding experimental values and with values obtained using other contracted Gaussian basis sets and numerical HF calculations. For all diatomic molecules studied, the differences between our total energies, obtained with the largest contracted basis set [6s5p3d1f], and those calculated with the numerical HF methods were always less than 3.2 mhartree.