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  • 1
    Electronic Resource
    Electronic Resource
    Electron correlation and relativistic effects in the coinage metal compounds (1995)
    Springer
    Theoretical chemistry accounts 92 (1995), S. 253-267 
    Details
    ISSN: 1432-2234
    Keywords: Dipole moments of CuH, AgH, AuH ; Electron correlation effects ; Relativistic effects ; Polarized basis sets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The first-order polarized basis sets of the coinage metal atoms have been used to perform high-level-correlated calculations of the dipole moment in the series of the MeH (Me=Cu, Ag, Au) molecules. The relativistic effects were accounted for by using the quasirelativistic approach based on the mass-velocity and Darwin terms in both the SCF HF and correlated level approximations. The non-relativistic coupled cluster calculations with complete treatment of one- and two-body clusters and perturbative correction for the three-body terms (CCSD(T) predict the following sequence of the dipole moment data: 1.13 a.u. for CuH, 1.35 a.u. for AgH, and 1.21 a.u. for AuH. Upon including the relativistic correction the calculated dipole moments turn out to be 1.05 a.u. for CuH, 1.14 for AgH, and 0.64 a.u. for AuH. The influence of the electron correlation and relativistic effects on the electronic distribution in the MeH molecules is discussed. A comparison of calculations with different number of explicitly correlated electrons gives an approximate scheme for the estimation of the core polarization/correlation contribution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01125950
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Standardized basis sets for high-level-correlated relativistic calculations of atomic and molecular electric properties in the spin-averaged Douglas-Kroll (no-pair) approximation I. Groups Ib and IIb (1996)
    Springer
    Theoretical chemistry accounts 94 (1996), S. 93-104 
    Details
    ISSN: 1432-2234
    Keywords: 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
    URL: http://dx.doi.org/10.1007/BF00194934
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Electric properties of the water molecule in 1A1, 1B1, and 3B1 electronic states: Refined CASSCF and CASPT2 calculations (1996)
    Springer
    Theoretical chemistry accounts 94 (1996), S. 75-91 
    Details
    ISSN: 1432-2234
    Keywords: Electric properties of excited states ; Dipole moments ; Dipole polarizabilities ; Excitation energies ; H2O ; CASSCF ; CASPT2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The dipole moments and dipole polarizabilities of the 1A1, 1B1, and 3B1 electronic states of the water molecule have been calculated by using the CASSCF approach followed by the evaluation of the dynamic electron correlation contribution by the second-order perturbation scheme CASPT2. All calculations have been carried out in a specifically extended ANO basis set which accounts for the Rydberg character of the two excited states. In order to estimate the correctness and accuracy of the present data a scan over a variety of different active spaces for the CASSCF wave function has been made. The present results are superior to earlier CASSCF calculations, although their qualitative features remain essentially the same. The dipole moments in 1B1 and 3B1 states are predicted to be about 0.49 a.u. and 0.33 a.u., respectively, and have the opposite orientation with respect to the ground state dipole moment. The dipole polarizability tensors of the excited states are characterized by high anisotropy and are dominated by the in-plane component perpendicular to the symmetry axis. All their components are found to be about an order of magnitude larger than those of the ground state polarizability tensor. The excitation energy dependence on the choice of the active orbital space in the CASSCF reference function is also considered and the analysis of the present data concludes in the concept of what is called the mutually compatible active spaces for the two states involved in excitation. All CASPT2 results are in good agreement with the results of recent calculations carried out in the framework of the open-shell coupled cluster formalism. This agreement confirms the high efficiency of the CASSCF/CASPT2 approach to the treatment of the electron correlation effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194933
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Standardized basis sets for high-level-correlated relativistic calculations of atomic and molecular electric properties in the spin-averaged Douglas-Kroll approximation II. Groups Ia and IIa (1997)
    Springer
    Theoretical chemistry accounts 96 (1997), S. 166-175 
    Details
    ISSN: 1432-2234
    Keywords: Key words: Polarized basis sets ; Relativistic effects ; Douglas-Kroll approximation ; Ionization potentials of group Ia and IIa metals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract. The technique previously developed 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 constructed for atoms of groups Ia and IIa of the Periodic Table and tested in calculations of atomic and ionic polarizabilities. Also the first ionization potential of the group Ia and the first and second ionization potential of the group IIa metals have been evaluated to provide additional qualification of the generated basis sets. The present results are compared with earlier non-relativistic and quasirelativistic data and the role of the relativistic effect is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002140050219
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    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Electron correlation and relativistic effects in the coinage metal compounds. I. The coinage metal hydrides (1995)
    Springer
    Theoretica chimica acta 92 (1995), S. 253-267 
    Details
    ISSN: 0040-5744
    Keywords: Key words: Dipole moments of CuH ; AgH ; AuH ; Electron correlation effects ; Relativistic effects ; Polarized basis sets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary.  The first-order polarized basis sets of the coinage metal atoms have been used to perform high-level-correlated calculations of the dipole moment in the series of the MeH (Me=Cu, Ag, Au) molecules. The relativistic effects were accounted for by using the quasirelativistic approach based on the mass–velocity and Darwin terms in both the SCF HF and correlated level approximations. The non-relativistic coupled cluster calculations with complete treatment of one- and two-body clusters and perturbative correction for the three-body terms (CCSD(T) predict the following sequence of the dipole moment data: 1.13 a.u. for CuH, 1.35 a.u. for AgH, and 1.21 a.u. for AuH. Upon including the relativistic correction the calculated dipole moments turn out to be 1.05 a.u. for CuH, 1.14 for AgH, and 0.64 a.u. for AuH. The influence of the electron correlation and relativistic effects on the electronic distribution in the MeH molecules is discussed. A comparison of calculations with different number of explicitly correlated electrons gives an approximate scheme for the estimation of the core polarization/correlation contribution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01125950
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Standardized basis sets for high-level-correlated relativistic calculations of atomic and molecular electric properties in the spin-averaged Douglas–Kroll (no-pair) approximation I. Groups Ib and IIb (1996)
    Springer
    Theoretica chimica acta 94 (1996), S. 93-104 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00194934
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Electric properties of the water molecule in 1A1, 1B1, and 3B1 electronic states: Refined CASSCF and CASPT2 calculations (1996)
    Springer
    Theoretica chimica acta 94 (1996), S. 75-91 
    Details
    ISSN: 0040-5744
    Keywords: Key words: Electric properties of excited states ; Dipole moments ; Dipole polarizabilities ; Excitation energies ; H2O ; CASSCF ; CASPT2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary.  The dipole moments and dipole polarizabilities of the 1A1, 1B1, and 3B1 electronic states of the water molecule have been calculated by using the CASSCF approach followed by the evaluation of the dynamic electron correlation contribution by the second-order perturbation scheme CASPT2. All calculations have been carried out in a specifically extended ANO basis set which accounts for the Rydberg character of the two excited states. In order to estimate the correctness and accuracy of the present data a scan over a variety of different active spaces for the CASSCF wave function has been made. The present results are superior to earlier CASSCF calculations, although their qualitative features remain essentially the same. The dipole moments in 1B1 and 3B1 states are predicted to be about 0.49 a.u. and 0.33 a.u., respectively, and have the opposite orientation with respect to the ground state dipole moment. The dipole polarizability tensors of the excited states are characterized by high anisotropy and are dominated by the in-plane component perpendicular to the symmetry axis. All their components are found to be about an order of magnitude larger than those of the ground state polarizability tensor. The excitation energy dependence on the choice of the active orbital space in the CASSCF reference function is also considered and the analysis of the present data concludes in the concept of what is called the mutually compatible active spaces for the two states involved in excitation. All CASPT2 results are in good agreement with the results of recent calculations carried out in the framework of the open-shell coupled cluster formalism. This agreement confirms the high efficiency of the CASSCF/CASPT2 approach to the treatment of the electron correlation effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194933
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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