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H Fukui - One of the best experts on this subject based on the ideXlab platform.
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Relativistic Calculation of nuclear magnetic shielding tensor using the regular approximation to the normalized elimination of the small component iii introduction of gauge including atomic orbitals and a finite size nuclear model
Journal of Chemical Physics, 2008Co-Authors: S Hamaya, H Maeda, M Funaki, H FukuiAbstract:The Relativistic Calculation of nuclear magnetic shielding tensors in hydrogen halides is performed using the second-order regular approximation to the normalized elimination of the small component (SORA-NESC) method with the inclusion of the perturbation terms from the metric operator. This computational scheme is denoted as SORA-Met. The SORA-Met Calculation yields anisotropies, Δσ=σ∥−σ⊥, for the halogen nuclei in hydrogen halides that are too small. In the NESC theory, the small component of the spinor is combined to the large component via the operator σ⋅πU/2c, in which π=p+A, U is a nonunitary transformation operator, and c≅137.036 a.u. is the velocity of light. The operator U depends on the vector potential A (i.e., the magnetic perturbations in the system) with the leading order c−2 and the magnetic perturbation terms of U contribute to the Hamiltonian and metric operators of the system in the leading order c−4. It is shown that the small Δσ for halogen nuclei found in our previous studies is...
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Relativistic Calculation of nuclear magnetic shielding tensor using the regular approximation to the normalized elimination of the small component ii consideration of perturbations in the metric operator
Journal of Chemical Physics, 2007Co-Authors: H Maeda, Yusuke Ootani, H FukuiAbstract:A previous Relativistic shielding Calculation theory based on the regular approximation to the normalized elimination of the small component approach is improved by the inclusion of the magnetic interaction term contained in the metric operator. In order to consider effects of the metric perturbation, the self-consistent perturbation theory is used for the case of perturbation-dependent overlap integrals. The Calculation results show that the second-order regular approximation results obtained for the isotropic shielding constants of halogen nuclei are well improved by the inclusion of the metric perturbation to reproduce the fully Relativistic four-component Dirac-Hartree-Fock results. However, it is shown that the metric perturbation hardly or does not affect the anisotropy of the halogen shielding tensors and the proton magnetic shieldings.
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Relativistic Calculation of nuclear magnetic shielding using normalized elimination of the small component
Journal of Chemical Physics, 2006Co-Authors: K Kudo, H Maeda, M Funaki, T Kawakubo, Yusuke Ootani, H FukuiAbstract:The normalized elimination of the small component (NESC) theory, recently proposed by Filatov and Cremer [J. Chem. Phys. 122, 064104 (2005)], is extended to include magnetic interactions and applied to the Calculation of the nuclear magnetic shielding in HX (X=F,Cl,Br,I) systems. The NESC Calculations are performed at the levels of the zeroth-order regular approximation (ZORA) and the second-order regular approximation (SORA). The Calculations show that the NESC-ZORA results are very close to the NESC-SORA results, except for the shielding of the I nucleus. Both the NESC-ZORA and NESC-SORA Calculations yield very similar results to the previously reported values obtained using the Relativistic infinite-order two-component coupled Hartree-Fock method. The difference between NESC-ZORA and NESC-SORA results is significant for the shieldings of iodine.
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Calculation of nuclear magnetic shieldings xv ab initio zeroth order regular approximation method
Journal of Chemical Physics, 2002Co-Authors: H Fukui, T BabaAbstract:An ab initio zeroth-order regular approximation (ZORA) theory for Relativistic Calculation of the nuclear magnetic shielding tensors is presented at the Hartree–Fock level. The nuclear magnetic shieldings tensors of hydrogen halides, HX (X=F, Cl, Br, and I), are calculated, and the results are compared to experimental values and other calculated results obtained using the Douglas–Kroll–Hess (DKH) transformation, the four-component random phase approximation (RPA), and the Dirac–Fock (DF) approaches. It is shown that the ZORA method underestimates the Relativistic effects on the magnetic shieldings as compared to the four-component RPA results. However, as to the proton chemical shifts, the ZORA results are closer to the experimental proton shifts than those of the DKH and 4-RPA approaches.
A Molinari - One of the best experts on this subject based on the ideXlab platform.
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delta isobar Relativistic meson exchange currents in quasielastic electron scattering
Nuclear Physics, 2003Co-Authors: J E Amaro, M B Barbaro, J A Caballero, T W Donnelly, A MolinariAbstract:We study the role of the ∆-isobar current on the response functions for high energy inclusive quasielastic electron scattering from nuclei. We consider a general Lagrangian which is compatible with contact invariance and perform a fully Relativistic Calculation in first-order perturbation theory for one-particle emission. The dependence of the responses upon off-shell parametrizations is analyzed and found to be mild. A discussion of scaling behaviour and a comparison with various non-Relativistic approaches are also presented. 2003 Elsevier Science B.V. All rights reserved.
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delta isobar Relativistic meson exchange currents in quasielastic electron scattering
arXiv: Nuclear Theory, 2003Co-Authors: J E Amaro, M B Barbaro, J A Caballero, T W Donnelly, A MolinariAbstract:We study the role of the $\Delta$-isobar current on the response functions for high energy inclusive quasielastic electron scattering from nuclei. We consider a general Lagrangian which is compatible with contact invariance and perform a fully Relativistic Calculation in first-order perturbation theory for one-particle emission. The dependence of the responses upon off-shell parametrizations is analyzed and found to be mild. A discussion of scaling behaviour and a comparison with various non-Relativistic approaches are also presented.
M B Barbaro - One of the best experts on this subject based on the ideXlab platform.
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delta isobar Relativistic meson exchange currents in quasielastic electron scattering
Nuclear Physics, 2003Co-Authors: J E Amaro, M B Barbaro, J A Caballero, T W Donnelly, A MolinariAbstract:We study the role of the ∆-isobar current on the response functions for high energy inclusive quasielastic electron scattering from nuclei. We consider a general Lagrangian which is compatible with contact invariance and perform a fully Relativistic Calculation in first-order perturbation theory for one-particle emission. The dependence of the responses upon off-shell parametrizations is analyzed and found to be mild. A discussion of scaling behaviour and a comparison with various non-Relativistic approaches are also presented. 2003 Elsevier Science B.V. All rights reserved.
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delta isobar Relativistic meson exchange currents in quasielastic electron scattering
arXiv: Nuclear Theory, 2003Co-Authors: J E Amaro, M B Barbaro, J A Caballero, T W Donnelly, A MolinariAbstract:We study the role of the $\Delta$-isobar current on the response functions for high energy inclusive quasielastic electron scattering from nuclei. We consider a general Lagrangian which is compatible with contact invariance and perform a fully Relativistic Calculation in first-order perturbation theory for one-particle emission. The dependence of the responses upon off-shell parametrizations is analyzed and found to be mild. A discussion of scaling behaviour and a comparison with various non-Relativistic approaches are also presented.
H Maeda - One of the best experts on this subject based on the ideXlab platform.
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Relativistic Calculation of nuclear magnetic shielding tensor using the regular approximation to the normalized elimination of the small component iii introduction of gauge including atomic orbitals and a finite size nuclear model
Journal of Chemical Physics, 2008Co-Authors: S Hamaya, H Maeda, M Funaki, H FukuiAbstract:The Relativistic Calculation of nuclear magnetic shielding tensors in hydrogen halides is performed using the second-order regular approximation to the normalized elimination of the small component (SORA-NESC) method with the inclusion of the perturbation terms from the metric operator. This computational scheme is denoted as SORA-Met. The SORA-Met Calculation yields anisotropies, Δσ=σ∥−σ⊥, for the halogen nuclei in hydrogen halides that are too small. In the NESC theory, the small component of the spinor is combined to the large component via the operator σ⋅πU/2c, in which π=p+A, U is a nonunitary transformation operator, and c≅137.036 a.u. is the velocity of light. The operator U depends on the vector potential A (i.e., the magnetic perturbations in the system) with the leading order c−2 and the magnetic perturbation terms of U contribute to the Hamiltonian and metric operators of the system in the leading order c−4. It is shown that the small Δσ for halogen nuclei found in our previous studies is...
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Relativistic Calculation of nuclear magnetic shielding tensor using the regular approximation to the normalized elimination of the small component ii consideration of perturbations in the metric operator
Journal of Chemical Physics, 2007Co-Authors: H Maeda, Yusuke Ootani, H FukuiAbstract:A previous Relativistic shielding Calculation theory based on the regular approximation to the normalized elimination of the small component approach is improved by the inclusion of the magnetic interaction term contained in the metric operator. In order to consider effects of the metric perturbation, the self-consistent perturbation theory is used for the case of perturbation-dependent overlap integrals. The Calculation results show that the second-order regular approximation results obtained for the isotropic shielding constants of halogen nuclei are well improved by the inclusion of the metric perturbation to reproduce the fully Relativistic four-component Dirac-Hartree-Fock results. However, it is shown that the metric perturbation hardly or does not affect the anisotropy of the halogen shielding tensors and the proton magnetic shieldings.
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Relativistic Calculation of nuclear magnetic shielding using normalized elimination of the small component
Journal of Chemical Physics, 2006Co-Authors: K Kudo, H Maeda, M Funaki, T Kawakubo, Yusuke Ootani, H FukuiAbstract:The normalized elimination of the small component (NESC) theory, recently proposed by Filatov and Cremer [J. Chem. Phys. 122, 064104 (2005)], is extended to include magnetic interactions and applied to the Calculation of the nuclear magnetic shielding in HX (X=F,Cl,Br,I) systems. The NESC Calculations are performed at the levels of the zeroth-order regular approximation (ZORA) and the second-order regular approximation (SORA). The Calculations show that the NESC-ZORA results are very close to the NESC-SORA results, except for the shielding of the I nucleus. Both the NESC-ZORA and NESC-SORA Calculations yield very similar results to the previously reported values obtained using the Relativistic infinite-order two-component coupled Hartree-Fock method. The difference between NESC-ZORA and NESC-SORA results is significant for the shieldings of iodine.
J E Amaro - One of the best experts on this subject based on the ideXlab platform.
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delta isobar Relativistic meson exchange currents in quasielastic electron scattering
Nuclear Physics, 2003Co-Authors: J E Amaro, M B Barbaro, J A Caballero, T W Donnelly, A MolinariAbstract:We study the role of the ∆-isobar current on the response functions for high energy inclusive quasielastic electron scattering from nuclei. We consider a general Lagrangian which is compatible with contact invariance and perform a fully Relativistic Calculation in first-order perturbation theory for one-particle emission. The dependence of the responses upon off-shell parametrizations is analyzed and found to be mild. A discussion of scaling behaviour and a comparison with various non-Relativistic approaches are also presented. 2003 Elsevier Science B.V. All rights reserved.
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delta isobar Relativistic meson exchange currents in quasielastic electron scattering
arXiv: Nuclear Theory, 2003Co-Authors: J E Amaro, M B Barbaro, J A Caballero, T W Donnelly, A MolinariAbstract:We study the role of the $\Delta$-isobar current on the response functions for high energy inclusive quasielastic electron scattering from nuclei. We consider a general Lagrangian which is compatible with contact invariance and perform a fully Relativistic Calculation in first-order perturbation theory for one-particle emission. The dependence of the responses upon off-shell parametrizations is analyzed and found to be mild. A discussion of scaling behaviour and a comparison with various non-Relativistic approaches are also presented.