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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical chemistry accounts 68 (1985), S. 431-444 
    ISSN: 1432-2234
    Keywords: Basis sets ; Perturbation-dependent basis sets ; Polarized basis sets ; Hellmann-Feynman theorem ; Infrared intensities ; Molecular properties ; H2O
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The idea of the basis set polarization which follows from the known dependence of basis set functions on the perturbation strength is applied to the calculation of the dipole moment derivatives with respect to nuclear displacements. The differentiation of the dipole moment function is replaced by the straightforward evaluation of derivatives of the intramolecular electric field with respect to the external electric field strength. The method and its efficiency are illustrated by a series of calculations of the dipole moment derivatives for the water molecule. Already a polarized basis set of 26 CGTO's derived from the minimal CGTO basis set provides fairly reasonable results.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2234
    Keywords: Finite-field many-body perturbation theory ; Basis sets ; Quadrupole moments ; Quadrupole polarizabilities ; H2 ; FH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The choice of truncated basis sets and their optimization for MBPT calculations of molecular properties are discussed. It is pointed out that computing the correlation corrections to some kth order property by using the MBPT approach requires the knowledge of accurate perturbed orbitals through the kth order. Hence, it is argued that the basis set functions can be optimized with respect to the perturbed energies calculated within the coupled Hartree-Fock method. The proposed procedure is illustrated by MBPT calculations of quadrupole moments of H2 and FH. Additionally, also some estimates of the quadrupole polarizability tensor components for these molecules are obtained.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0040-5744
    Keywords: Key words: Polarized basis sets ; Electric dipole polarizabilities of Zn ; Cd ; Hg ; and their positive ions ; Electron correlation effects on atomic properties ; Relativistic effects on atomic properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary. The first-order polarized basis sets are generated for Zn, Cd, and Hg and their performance is tested in high-level-correlated calculations of electric dipole polarizabilities of these atoms. The present results calculated at the level of the non-relativistic CCSD(T) approximation with 12 explicitly correlated electrons are: 40.4 a.u. for Zn, 56.3 a.u. for Cd, and 58.0 a.u. for Hg. Upon including the relativistic and electron correlation–relativistic corrections within the quasirelativistic scheme based on the mass–velocity and Darwin terms these values are reduced to 37.9 a.u., 47.6 and 31.8 a.u., respectively. The derived polarized basis sets have been also used for the evaluation of the dipole polarizability of singly and doubly positive ions of the group IIb elements and are recommended for calculations of interaction energies and interaction-induced electric properties in both neutral and charged systems.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0040-5744
    Keywords: Key words: Polarized basis sets ; Dipole polarizabilities of Cu ; Ag ; and Au ; Dipole polarizabilities of Cu+ ; Ag+ ; and Au+ ; Relativistic effects on atomic electric properties ; Electron correlation effects on atomic electric properties ; Relativistic ; correlation corrections ; SA CCSD(T) method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary.  The first-order polarized basis sets PolMe are generated for elements (Me=Cu, Ag, Au) of group Ib of the periodic table by using the basis set polarization method developed in earlier papers. The performance of these basis sets is extensively tested in calculations of atomic dipole polarizabilities with particular attention given to the evaluation of the electron correlation and relativistic contributions. The extension by the g-type polarization functions (PolMe-g sets) is devised for use in accurate calculations of atomic and molecular electric properties. The (negative) electron correlation contribution to dipole polarizabilities of all elements of group Ib, as calculated at the level of the spin adapted coupled cluster method with single and double excitations and non-iterative corrections for the contribution of the T3 clusters (SA CCSD(T)), remains at the same level relative to the ROHF data. The pure relativistic correction to the ROHF results, evaluated within the quasirelativistic approximation involving the mass–velocity and Darwin corrections, is negative and rapidly increases with increase of the nuclear charge. Its large negative value is, for heavier systems, partly compensated by a positive contribution from the mixed relativistic–correlation terms. Our relativistically corrected SA CCSD(T) calculations predict the following values of the dipole polarizability in the coinage metal series: 46, 51, and 29 a.u., for Cu, Ag, and Au. The present results for Cu and Ag agree well with recent pseudopotential calculations by Schwerdtfeger and Bowmaker. However, for Au our result is by about 6 a.u. lower than that obtained by using 19-electron relativistic potentials. Several possible reasons for this discrepancy are discussed. The PolMe and PolMe-g basis sets are also used to calculate electric dipole polarizabilities of the singly positive ions of group Ib elements. The results obtained in the quasirelativistic CCSD(T) approximation are 6.6, 9.2, and 11.8 a.u. for Cu+, Ag+, and Au+, respectively. These values follow the pattern expected for the series of ions whose polarizability is dominated by the next-to-valence d shell.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0040-5744
    Keywords: Key words: Polarized basis sets ; Relativistic effects ; Douglas ; Kroll no-pair approximation ; Dipole polarizabilities of Zn ; Cd ; Hg ; Dipole moments of CuH ; AgH ; and AuH ; Polarizabilities of atomic ions: Cu+ ; Ag+ ; Zn2+ ; Cd2+ ; Hg2+
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary.  The technique developed earlier for the generation of the so-called first-order polarized basis sets for accurate non-relativistic calculations of molecular electric properties is used to obtain similar basis sets suitable for calculations in the Douglas–Kroll no-pair approximation. The corresponding (relativistic) basis sets are devised for atoms of the Groups Ib and IIb of the periodic table and tested in calculations of atomic polarizabilities and dipole moments of the coinage metal hydrides. Excellent performance of these basis sets has been found in the case of molecular calculations.
    Type of Medium: Electronic Resource
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