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Title: Determination of nuclear quadrupole moments – An example of the synergy of ab initio calculations and microwave spectroscopy

Abstract

Highly correlated scalar relativistic calculations of electric field gradients at nuclei in diatomic molecules in combination with accurate nuclear quadrupole coupling constants obtained from microwave spectroscopy are used for determination of nuclear quadrupole moments.

Authors:
 [1]
  1. Department of Physical Chemistry, Comenius University, SK-842 15 Bratislava (Slovakia)
Publication Date:
OSTI Identifier:
22390886
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1642; Journal Issue: 1; Conference: ICCMSE-2010: International Conference of Computational Methods in Sciences and Engineering 2010, Kos (Greece), 3-8 Oct 2010; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COUPLING CONSTANTS; ELECTRIC FIELDS; MICROWAVE RADIATION; MOLECULES; QUADRUPOLE MOMENTS; RELATIVISTIC RANGE; SCALARS; SPECTROSCOPY

Citation Formats

Kellö, Vladimir. Determination of nuclear quadrupole moments – An example of the synergy of ab initio calculations and microwave spectroscopy. United States: N. p., 2015. Web. doi:10.1063/1.4906652.
Kellö, Vladimir. Determination of nuclear quadrupole moments – An example of the synergy of ab initio calculations and microwave spectroscopy. United States. doi:10.1063/1.4906652.
Kellö, Vladimir. 2015. "Determination of nuclear quadrupole moments – An example of the synergy of ab initio calculations and microwave spectroscopy". United States. doi:10.1063/1.4906652.
@article{osti_22390886,
title = {Determination of nuclear quadrupole moments – An example of the synergy of ab initio calculations and microwave spectroscopy},
author = {Kellö, Vladimir},
abstractNote = {Highly correlated scalar relativistic calculations of electric field gradients at nuclei in diatomic molecules in combination with accurate nuclear quadrupole coupling constants obtained from microwave spectroscopy are used for determination of nuclear quadrupole moments.},
doi = {10.1063/1.4906652},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1642,
place = {United States},
year = 2015,
month = 1
}
  • We present here ab initio determinations of the nuclear-quadrupole moment Q of hyperfine-probe-nuclear states of three different In isotopes: the 5{sup +} 192 keV excited state of {sup 114}In (probe for nuclear quadrupole alignment spectroscopy), the 9/2{sup +} ground state of {sup 115}In (nuclear magnetic and nuclear quadrupole resonance probe), and the 3/2{sup +} 659 keV excited state of {sup 117}In (perturbed angular correlations probe). These nuclear-quadrupole moments were determined by comparing experimental nuclear-quadrupole frequencies to the electric field gradient tensor calculated with high accuracy at In sites in metallic indium within the density functional theory. These ab initio calculationsmore » were performed with the full-potential linearized augmented plane wave method. The results obtained for the quadrupole moments of {sup 114}In [Q({sup 114}In)=-0.14(1) b] are in clear discrepancy with those reported in the literature [Q({sup 114}In)=+0.16(6) b and +0.739(12) b]. For {sup 115}In and {sup 117}In our results are in excellent agreement with the literature and in the last case Q({sup 117}In) is determined with more precision. In the case of Q({sup 117}In), its sign cannot be determined because standard {gamma}-{gamma} perturbed angular correlations experiments are not sensitive to the sign of the nuclear-quadrupole frequency.« less
  • The authors report new calculations for the nuclear quadrupole moments of {sup 11}C, {sup 17}O, and {sup 21}Ne, making use of a new finite-element multiconfiguration Hartree-Fock method. They calculate electric field gradients at the nuclei and combine these with measurements of nuclear quadrupole coupling constants to arrive at the values.
  • The hyperfine parameters for B({sup 2}{ital P}) are studied using numerical multiconfiguration Hartree--Fock (MCHF) calculations. A newly developed finite-element MCHF program allowing very large configuration--interaction expansions is used. The magnetic hyperfine parameters obtained are 0.0879(28), 0.7817(11), and {minus}0.1675(3) a.u. for the Fermi contact term, the orbital term, and the spin--dipolar term, respectively, as compared to the experimental values of 0.1016(62), 0.7783(16), and {minus}0.1686(5) a.u. The nuclear quadrupole moments obtained by comparing computed electric field gradients with experimental nuclear quadrupole couplings constants are {ital Q}({sup 10}B)=0.084 59(24) {ital b} and {ital Q}({sup 11}B)=0.040 59(10) {ital b}.
  • The electric field gradient in late transition metal compounds is incorrectly determined by most density functionals. We show that the coupling of short-range density functional based with long-range wave function based methods using a reparametrization of the Coulomb-attenuated Becke three-parameter Lee-Yang-Parr approximation gives reliable results for the electric field gradients of copper and gold for a series of compounds. This results in nuclear quadrupole moments of -0.208 b for {sup 63}Cu and +0.526 b for {sup 197}Au in good agreement with experimental values of -0.220(15) and +0.547(16)b, respectively.