Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Finite-field many-body perturbation theory II. SD-MBPT study of the nuclear charge dependence of the electron correlation contribution to the dipole polarizability of 10-electron atomic systems (1982)
    Springer
    Theoretical chemistry accounts 61 (1982), S. 485-504 
    Details
    ISSN: 1432-2234
    Keywords: Finite-field many-body perturbation theory ; Dipole-polarizability ; Nuclear charge dependence ; 10-Electron atomic systems ; F− ; Ne ; Na+
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The finite-field many-body perturbation theory limited to intermediate states involving single and double substitutions in the reference HF determinant is applied to the calculation of dipole polarizabilities of 10-electron atomic systems. The nuclear charge dependence of the convergence of the SD-MBPT series for correlation corrections to the dipole polarizability is investigated. It is concluded that the fourth-order SD-MBPT scheme is quite appropriate for neutral and positively charged species. For negatively charged systems the convergence of the SD-MBPT series becomes much poorer and including higher-order substitutions may be necessary. The role of the renormalization contributions to the SD-CI polarizability results is also considered. It follows that the corresponding data need to be corrected for the erratic treatment of unlinked clusters. The size inconsistency effects make quite important contributions to the SD-CI values of the correlation corrections to dipole polarizabilities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00549039
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Approximate variation-perturbation calculations of the second-order molecular properties (1971)
    Springer
    Theoretical chemistry accounts 21 (1971), S. 159-167 
    Details
    ISSN: 1432-2234
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Das Variations-Störungsverfahren wird im Rahmen der CNDO/2-Näherung zur Berechnung von elektrischen Polarisierungstensoren zweiatomiger Moleküle herangezogen. Die Resultate ähneln denen des analogen, aber auf ab initio-Rechnungen basierenden Verfahrens mit einem minimalen Satz von Slaterfunktionen. Es ergibt sich, daß die Berechnung der Anisotropien nicht möglich ist, wohl aber die der räumlichen Mittelwerte.
    Notes: Abstract The variation-perturbation technique is applied to the calculation of the electric polarizability tensor of diatomic molecules within the CNDO/2 approximation. The results obtained in this paper are similar to those found in the non-empirical variation-perturbation approach within the minimal STO basis set. They are also compared with other CNDO/2 calculations and with existing experimental data. It follows from this comparison that the CNDO/2 variation-perturbation method does not allow for the calculation of the polarizability anisotropies. On the other hand, the rotational average of the polarizability tensor can be predicted in agreement with both the experimental data and nonempirical results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00530213
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Finite-field many-body perturbation theory. Calculations of the dipole polarizability of the fluoride ion using electric-field-variant gaussian-type orbitals (1981)
    Springer
    Theoretical chemistry accounts 60 (1981), S. 19-39 
    Details
    ISSN: 1432-2234
    Keywords: Many-body perturbation theory ; Finite-field method ; Dipole polarizability ; Electric-field-variant basis set
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The dipole polarizability of the fluoride ion, F−, is calculated using finite-field many-body perturbation theory. The use of electric-field-variant basis sets in such calculations is investigated. Scaling of the zero-order Hamiltonian and the formation of Padé approximants are considered. Empirical and theoretical estimates of the polarizability of F− are compared.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00554384
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Basis set superposition effects on properties of interacting systems. Dipole moments and polarizabilities (1982)
    Springer
    Theoretical chemistry accounts 61 (1982), S. 1-9 
    Details
    ISSN: 1432-2234
    Keywords: Basis set superposition effect ; Molecular properties ; Molecular interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Basis set superposition effects which are not removed by the counterpoise correction are shown to modify the electric properties of interacting subsystems and influence indirectly the calculated interaction energies. The role of these higher-order basis set superposition effects is illustrated by the calculation of the water molecule dipole moment and polarizability in the basis set of the water dimer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00573859
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Proton magnetic shielding in the water molecule (1972)
    Springer
    Theoretical chemistry accounts 27 (1972), S. 135-145 
    Details
    ISSN: 1432-2234
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die ungekoppelte Hartree-Fock Variationsstörungsrechnung von Karplus u. Kolker wird für die Berechnung von Eigenschaften 2. Ordnung des Wassermoleküls verwendet. Für die Berechnung wird die SCF MO SCGO-Wellenfunktion des Grundzustandes gewählt, und die gestörten Orbitale 1. Ordnung werden in der multiplikativen Form approximiert. Die Konvergenz der Methode und die Frage, ob die Eichinvarianz verletzt wird, werden untersucht. Für den gewählten Potential-Nullpunkt im Zentrum der negativen Ladungsverteilung beträgt die errechnete Protonenabschirmungskonstante 28,30 ppm in guter Übereinstimmung mit den experimentellen Werten (30.20, 30.03 + 0.60 ppm). Die Ergebnisse für die magnetische Suszeptibilität des Wassermoleküls sind gleichfalls in vernünftiger Übereinstimmung mit dem Experiment.
    Notes: Abstract The variation-perturbation uncoupled Hartree-Fock procedure of Karplus and Kolker is employed for the calculation of the second-order properties of the water molecule. The SCF MO LCGO ground state wave function was chosen and the first-order perturbed orbitals were approximated in the multiplicative form. The convergence of the method as well as the violation of the gauge independence are studied. For the preferred gauge origin at the electronic centroid the calculated proton shielding constant is 28.30 ppm and compares favourably with the experimental data (30.20, 30.03 ±0.60 ppm). The results for the magnetic susceptibility of the water molecule are also in reasonable agreement with experimental values.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00528156
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Proton magnetic shielding in H2O and (H2O)2 (1973)
    Springer
    Theoretical chemistry accounts 30 (1973), S. 257-265 
    Details
    ISSN: 1432-2234
    Keywords: Proton magnetic shielding ; Hydrogen bond NMR shift of water molecule and dimer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The proton magnetic shielding constants in the water molecule and its linear perpendicular dimer are computed from SCF-MO-LCGO wave functions by using the uncoupled Hartree-Fock variation-perturbation procedure due to Karplus and Kolker. The convergence of the calculated shielding constants as well as their gauge dependence is studied. The final results for 17-term polynomial variation function indicate that the best choice for the gauge origin corresponds to the molecular electronic centroid. The calculated proton magnetic shielding constant in the water molecule is in remarkable agreement with experimental data and favourably compares with the best coupled Hartree-Fock results. It follows from the calculations for the water dimer that the H-bond NMR-shift amounts in this case —1.0 ppm and qualitatively agrees with the experimental data for the liquid water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00527616
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Finite-field many-body perturbation theory IV. Basis set optimization in MBPT calculations of molecular properties. Molecular quadrupole moments (1983)
    Springer
    Theoretical chemistry accounts 63 (1983), S. 69-82 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00549156
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Correlation effects in externally perturbed many-electron systems (1983)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 23 (1983), S. 147-167 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Different methods for the calculation of the electron correlation contribution to atomic and molecular properties are analyzed and evaluated. The methods based on the self-consistent solution of the external perturbation problem are shown to offer several formal and computational advantages. The analysis of the correlation perturbation series for properties of many-electron systems indicates the importance of the appropriate treatment of unlinked diagrammatic contributions. In particular, the standard limited configuration interaction scheme based on single and double substitutions in the reference function may significantly suffer from the erratic treatment of unlinked clusters and needs to be corrected appropriately. The basis set choice for the calculation of highly accurate values of properties is also discussed. In order to circumvent the dimensionality problem the use of basis sets with explicit dependence on the external perturbation strength is recommended and methods for their choice and optimization are presented. A particular attention is paid to the many-body perturbation theory involving singly and doubly substituted intermediate states and based on the coupled Hartree-Fock solution for the one-electron perturbation problem. Different computational aspects of this method are discussed and compared with other techniques currently in use.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560230116
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    14N chemical shifts in the enamino ketone quaternary ammonium salts (1971)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 3 (1971), S. 589-594 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 14N chemical shifts were measured for a series of quaternary ammonium salts of enamino ketones. An upfield shift of the 14N resonance signals upon quaternization has been observed. The interpretation in terms of the approximate theory of nuclear magnetic shielding is given. The calculations for some model systems result in a general agreement with the experimental data.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270030514
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    CNDO calculations of diamagnetic shielding in molecules (1970)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 2 (1970), S. 63-69 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An approximate procedure for the calculation of diamagnetic shielding in molecules is presented. The method proposed is based on the ‘complete neglect of differential overlap’ (CNDO) molecular wave functions and is formulated according to the zero differential overlap (ZDO) approximation. The results obtained with several CNDO-type wave functions for diatomic and polyatomic molecules are in very good agreement with non-empirical SCF calculations. The 14N diamagnetic shielding constants in several molecules were computed and some approximations usually adopted in the interpretation of 14N chemical shifts are critically discussed. It was shown that in some cases the observed 14N chemical shifts cannot be interpreted solely in terms of the paramagnetic contribution to the shielding constant.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270020108
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...