Nuclear quadrupole moments from molecular microwave data: The quadrupole moment of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>85</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">Rb</mml:mi></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>87</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">Rb</mml:mi

Kellö, Vladimı́r; Sadlej, Andrzej J.

doi:10.1103/physreva.60.3575

Cited by 37 publications

(11 citation statements)

References 54 publications

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“…The effect of this removal of high-energy virtuals and the effect of electron correlation due to deeper lying shells was, however, calculatgd at the MP2 level of theory and used to correct the CCSD(T) values. This two-step strategy to calculate the electron correlation effects to the EFG was initially proposed by Kello and and coworkers [42,431 and works quite well if core contributions are small.…”

Section: Methods and Computational Detailsmentioning

confidence: 99%

Molecular relativistic electric field gradient calculations suggest revision of the value of the nuclear electric quadrupole moment of 127I

Stralen

Visscher

2003

Mol. Phys.

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Relativistic ab initio methods are used to compute the electric field gradient at the iodine nucleus in nine different closed-shell diatomic molecules. Combining these theoretical electric field gradients with experimental nuclear quadrupole coupling constants gives a consistent value of the nuclear quadrupole moment of Iz7I of -696(12)millibarn. We argue that this value is more precise than the current standard value of the nuclear quadrupole moment of Iz7I and recommend adjusting the reference value accordingly. The precision of this determination is still determined by technical limitations in the theoretical work, in particular the neglect of the two-electron Gaunt interaction in the Hamiltonian and correlation contributions beyond those described at the CCSD(T) level of theory, but the errors are reduced relative to the theoretical work that underlies the current standard value of this nuclear quadrupole moment. As a secondary study we also considered the calculation of the small electric field gradient at the gold nucleus in the AuI molecule and conclude that this computation remains a challenge for theoreticians.

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Section: Methods and Computational Detailsmentioning

confidence: 99%

Molecular relativistic electric field gradient calculations suggest revision of the value of the nuclear electric quadrupole moment of 127I

Stralen

Visscher

2003

Mol. Phys.

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“…Basis sets are uncontracted to allow for sufficient flexibility in the description of the core region. 63,64 All correlated calculations started with a HF calculation on a molecule with one additional electron followed by a Fock space CC calculation of the ionization energies thereof to obtain the SO splitting of the neutral molecule. This is necessary as the Fock space method needs a single reference state from which the active space is constructed.…”

Section: Computational Detailsmentioning

confidence: 99%

The molecular mean-field approach for correlated relativistic calculations

Sikkema

Visscher

Saue³

et al. 2009

The Journal of Chemical Physics

219

226

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A new approach for relativistic correlated electron structure calculations is proposed by which a transformation to a two-spinor basis is carried out after solving the four-component relativistic Hartree-Fock equations. The method is shown to be more accurate than approaches that apply an a priori transformation to a two-spinor basis. We also demonstrate how the two-component relativistic calculations with properly transformed two-electron interaction can be simulated at the four-component level by projection techniques, thus allowing an assessment of errors introduced by more approximate schemes.

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“…These are computationally much more demanding, but can in principle provide an arbitrary high precision. The recent literature [29,[73][74][75][76][77] shows that coupled cluster theory with single, double, and (perturbatively) triple excitations [CCSD(T)], combined with sufficiently large basis sets and-where needed-with a (semi)relativistic Hamiltonian, provides highly accurate EFGs for small molecules. It has been claimed [78] that in this way an absolute accuracy with four significant digits can be reached.…”

Section: A Accuracy Of Quadrupole Interaction Experiments and Calculmentioning

confidence: 99%

Electron penetration into the nucleus and its effect on the quadrupole interaction

et al. 2010

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A series expansion of the interaction between a nucleus and its surrounding electron distribution provides terms that are well-known in the study of hyperfine interactions: the familiar quadrupole interaction and the less familiar hexadecapole interaction. If the penetration of electrons into the nucleus is taken into account, various corrections to these multipole interactions appear. The best known correction is a scalar term related to the isotope shift and the isomer shift. This paper discusses a related tensor correction, which modifies the quadrupole interaction if electrons penetrate the nucleus: the quadrupole shift. We describe the mathematical formalism and provide first-principles calculations of the quadrupole shift for a large set of solids. Fully relativistic calculations that explicitly take a finite nucleus into account turn out to be mandatory. Our analysis shows that the quadrupole shift becomes appreciably large for heavy elements. Implications for experimental high-precision studies of quadrupole interactions and quadrupole moment ratios are discussed. A literature review of other small quadrupole-like effects is presented as well (pseudoquadrupole effect, isotopologue anomaly, etc.).

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Nuclear quadrupole moments from molecular microwave data: The quadrupole moment of85Rband87Rb

Cited by 37 publications

References 54 publications

Molecular relativistic electric field gradient calculations suggest revision of the value of the nuclear electric quadrupole moment of 127I

Molecular relativistic electric field gradient calculations suggest revision of the value of the nuclear electric quadrupole moment of 127I

The molecular mean-field approach for correlated relativistic calculations

Electron penetration into the nucleus and its effect on the quadrupole interaction

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