Contracted Gaussian basis sets for Douglas–Kroll–Hess calculations: Estimating scalar relativistic effects of some atomic and molecular properties

Abstract

Douglas-Kroll-Hess (DKH) contracted Gaussian basis sets of double, triple, and quadruple zeta valence qualities plus polarization functions (XZP, X=D, T, and Q, respectively) for the atoms H-Ar and DZP and TZP for K-Kr are presented. They have been determined from the corresponding nonrelativistic basis sets generated previously by Jorge et al. We have recontracted the original XZP basis sets, i.e., the values of the contraction coefficients were reoptimized using the relativistic DKH Hamiltonian. The effect of DKH at the coupled-cluster level of theory on the ionization energy of some atoms and dissociation energy and geometric parameters for a sample of molecules is discussed. Our results were compared with theoretical and experimental values reported in the literature.

Positron-electron correlation-polarization potentials for the calculation of positron collisions with atoms and molecules*

“…For Kr the active space is generated by 8 active electrons in the orbitals (4s, 4p, 4d, 5s, 5p, 6s, 6p), which results in 415 306 determinants. We are using the contracted gaussian basis set for Douglas-Kroll-Heß calculations of triple zeta valence quality plus polarization functions (TZP-DKH) of Jorge et al [52], which we obtained from the EMSL Basis Set Library [53,54]. The DouglasKroll-Heß method [55,56] is used to account for scalar relativistic effects of the target wave function.…”

Do positrons measure atomic and molecular diameters?

“…Electronelectron correlation is considered through the complete The contracted gaussian basis set for Douglas-KrollHeß calculations of triple zeta valence quality plus polarization functions (TZP-DKH) of Jorge et al [36] are used. The TZP-DKH basis set has the contraction scheme (13s, 10p, 2d, 1f ) → (8s, 5p, 2d, 1f ) for Ar and (16s, 13p, 6d, 2f, 1g) → (9s, 6p, 3d, 2f, 1g) for Kr.…”

Jensen–Shannon and Kullback–Leibler divergences as quantifiers of relativistic effects in neutral atoms

“…the asymptotic behavior of atomic ionization potentials for large Z or bond lengths and molecular geometries [1,2]. Some other important atomic and molecular properties, such as dipole polarizabilities, electron affinities, excitation energies, dipole moments or correlation and structure effects are the object of recent studies and modern computations in the relativistic framework [3,4]. In order to take into account the relativistic effects, the Dirac-Fock equation must be solved, enclosing the Schrödinger one as the nonrelativistic limit.…”