ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
    Selected topics in ab initio computational chemistry in both very small and very large chemical systems (1991)
    s.l. : American Chemical Society
    Chemical reviews 91 (1991), S. 679-699 
    Details
    ISSN: 1520-6890
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/cr00005a003
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The multiconfigurational spin tensor electron propagator method (MCSTEP): Electron affinities of Li, Na, and K (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 5451-5454 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The multiconfigurational spin tensor electron propagator approximation to the electron propagator is applied for the first time to the calculation of electron affinities. The electron affinities of Li, Na, and K are calculated as the ionization potentials of the negative ions. On average these electron affinities differ from experiment by 0.003 eV, giving the best theoretical values reported to data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.457546
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Application of the multiconfiguration time-dependent Hartree–Fock method to CH+: The auxiliary active space (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 3063-3070 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The multiconfigurational time-dependent Hartree–Fock (MCTDHF) method is used to study the excitation energies and transition moments of the CH+ ion. A consistent approach to the selection of configurations based on the complete active space (CAS) model is successfully applied. In this approach a large set of orbitals is included in the active space without a substantial increase in the number of configurations, since only for a smaller subset of orbitals is the configuration expansion complete and the remaining orbitals active are considered an auxiliary set. For CH+ the active space includes the valence and additional orbitals, with the valence orbitals constituting the complete subset. Extra configurations involving single and double excitations from the valence to the additional (auxiliary) orbitals are included both for the MCSCF reference state and in the MCTDHF. It is demonstrated that this active space accurately mimics MCSCF and MCTDHF calculations with an enlarged complete active space which includes both the original CAS and the auxiliary orbitals. The calculations for the 1 Π and 1 Σ+ excited states at the equilibrium geometry show that accurate excitation energies and transition moments are obtained in this way. For most of these states for which there are other good ab initio results available, we obtain comparable excitation energies and transition moments. In addition to 1 Π and 1 Σ+ , low lying states of other symmetries are obtained and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454962
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Characteristics and some peculiarities of multiconfigurational self-consistent field stationary points of the Li− ground state (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 8011-8020 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We examine in detail the multiconfigurational self-consistent field (MCSCF) energy hypersurface of the ground state of Li− using a previously reported Cartesian Gaussian basis set and several previously used different choices of complete active space (CAS). For many of the CASs we show there are many close-lying (in energy) stationary points that have the correct number of negative eigenvalues in the total Hessian with respect to real variations of the orbital and configurational parameters and correspond to the lowest energy eigenvector in the configuration interaction (CI) which uses the MCSCF orbitals and configurations. These stationary points may be obtained with any of the current, forefront MCSCF codes. More detailed examination of these stationary points shows that some of these are improper and that some do not correspond to the most "desired'' stationary point. The presence of two nearby proper, desired MCSCF stationary points with the 2–3s, 2–3p CAS is troubling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.459330
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Erratum: The multiconfigurational spin tensor electron propagator method: Electron affinities of Li, Na, and K [J. Chem. Phys. 91, 5451 (1989)] (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 6336-6337 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.458607
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Accurate transition moments between the A 3Σ+u, B 3Πg, and B' 3Σ−u of N2 using multiconfigurational linear response (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 1533-1539 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Accurate values of the electronic transition moment function for the first positive (A 3∑+u−B 3Πg) and infrared afterglow (B 3Πg −B'3∑−u) systems of N2 were obtained through multiconfigurational linear response (also known as the multiconfigurational time-dependent Hartree–Fock, MCLR/MCTDHF). MCLR/MCTDHF furnished both excitation energies and transition moments. MCLR/MCTDHF calculations on the first positive system demonstrate the importance of configurations involving the 2σg orbital. To obtain accurate values, configurations were chosen with a complete active space of all valence orbitals (2σg, 2σu, 1πu, 3σg, 1πg, 3σu). This is the first MCLR/MCTDHF calculation for molecules as large as first row diatomics in which a complete active space including the entire valence shell is employed. The results are in substantial agreement with accurate theoretical calculations by others and, hence, disagree in their overall behavior with the previously published empirical values. One of our conclusions is that the experimental values for the first positive system far from the equilibrium region are in error.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.455151
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The effect of intermolecular interactions on the electric properties of helium and argon. III. Quantum statistical calculations of the dielectric second virial coefficients (2002)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 117 (2002), S. 2609-2618 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The second dielectric virial coefficients of helium and argon are investigated using a fully quantum statistical approach and recent accurate ab initio results for the interatomic potentials and the interaction-induced polarizabilities. We thereby extend a preceding investigation based on a semiclassical approach to include quantum effects. For helium the results support the findings of a previous study by Moszynski et al. [J. Chem. Phys. 247, 440 (1995)] that quantum effects are substantial for temperatures below 10 K, while they are practically negligible above 70 K. For argon special care is needed in the numerical integrations carried out in the quantum statistical calculation of the virial coefficients, due to the presence of quasibound states in the continuum and a slow convergence of the summation over the angular momentum. Here quantum effects are practically negligible in the range of temperatures experimentally investigated, i.e., between 243 and 408 K. As far as comparison with experimental data is concerned, large discrepancies are found for some of the low-temperature experimental measurements of helium. Agreement is also unsatisfactory for high temperatures for argon and experimental redetermination is suggested. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1491402
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Shielding polarizabilities calculated at the coupled-cluster singles and doubles level augmented by a perturbative treatment of triple excitations (2002)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 116 (2002), S. 869-877 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The nuclear magnetic shielding polarizabilities of N2, F2, CO, HF, HCl, HCN, HNC, and C2H2 have been computed at the coupled-cluster singles and doubles (CCSD) level augmented by a perturbative treatment of triple excitations [CCSD(T)] using gauge-including atomic orbitals and a mixed analytical-numerical approach based on the numerical differentiation of analytically evaluated shieldings. Extended basis sets have been employed to ensure results close to the basis set limit, and convergence of the electron-correlation treatment is investigated. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1425405
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Ab initio study of the electric-field-gradient-induced birefringence of a polar molecule: CO (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 113 (2000), S. 3077-3087 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: An ab initio coupled cluster singles and doubles (CCSD) investigation of the electric-field- gradient-induced birefringence (EFGB) of a polar molecule, CO, is presented. The so-called "effective quadrupole center" (EQC), the origin to which the quadrupole moment deduced from EFGB experiments refers for dipolar molecules and which experimentalists cannot determine directly, is computed within two different semiclassical theories of the EFGB. The temperature independent frequency dependent contribution to the birefringence is determined as well. The molecular electric quadrupole moment with the origin at the EQC is determined within the two theories via an accurate value of the quadrupole moment referring to the center of mass, obtained using well-established hierarchies of basis sets and wave function models, and the calculated EQCs. The final theoretical values result as the basis set limit at the CCSD(T) level completed with estimates for relativistic effects, correlation contributions beyond CCSD(T), rovibrational effects, and residual errors in the EQC. The comparison of the theoretical results with the corresponding experimentally deduced values sheds some light on the differences between the two semiclassical approaches to the EFGB. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1287057
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Electric field dependence of magnetic properties: Multiconfigurational self-consistent field calculations of hypermagnetizabilities and nuclear shielding polarizabilities of N2, C2H2, HCN, and H2O (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 8953-8966 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Multiconfigurational self-consistent field (MCSCF) response is used to study the electric field dependence of magnetizabilities and nuclear shielding constants for N2, C2H2, HCN, and H2O. London perturbation-dependent atomic orbitals are used to ensure gauge origin independence. The computed magnetizabilities and shielding derivatives show a strong electron correlation dependence. The N2 results confirm the conclusions of previous ab initio studies. For the other molecules, this is the first study of the above magnetic properties beyond the SCF approximation. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.468949
    Location Call Number Expected 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...