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The quadrupole moment of the 3/2+ nuclear ground state of Au197 from electric field gradient relativistic coupled cluster and density-functional theory of small molecules and the solid state
The Journal of Chemical Physics (2005)
  • Peter Schwerdtfeger, Massey University
  • Radovan Bast
  • Michael C.L. Gerry, University of British Columbia
  • Christoph R. Jacobs
  • Martin Jansen
  • Vladimir Kello
  • Anja V. Mudring
  • Andrzej J. Sadlej
  • Trond Saue
  • Tilo Sohnel, University of Auckland
  • Friedrich E. Wagner
Abstract

An attempt is made to improve the currently accepted muonic value for the Au197 nuclear quadrupole moment [+0.547(16)×10−28m2] for the 3/2+ nuclear ground state obtained by Powers et al. [Nucl. Phys.A230, 413 (1974)]. From both measured Mössbauer electric quadrupole splittings and solid-state density-functional calculations for a large number of gold compounds a nuclear quadrupole moment of +0.60×10−28m2 is obtained. Recent Fourier transform microwave measurements for gas-phase AuF, AuCl, AuBr, and AuI give accurate bond distances and nuclear quadrupole coupling constants for the Au197isotope. However, four-component relativistic density-functional calculations for these molecules yield unreliable results for the Au197 nuclear quadrupole moment. Relativistic singles-doubles coupled cluster calculations including perturbative triples [CCSD(T) level of theory] for these diatomic systems are also inaccurate because of large cancellation effects between different field gradient contributions subsequently leading to very small field gradients. Here one needs very large basis sets and has to go beyond the standard CCSD(T) procedure to obtain any reliable field gradients for gold. From recent microwave experiments by Gerry and co-workers [Inorg. Chem.40, 6123 (2001)] a significantly enhanced Au197 nuclear quadrupole coupling constant in (CO)AuF compared to free AuF is observed. Here, these cancellation effects are less important, and relativistic CCSD(T) calculations finally give a nuclear quadrupole moment of +0.64×10−28m2 for Au197. It is argued that it is currently very difficult to improve on the already published muonic value for the Au197 nuclear quadrupole moment.

Publication Date
2005
Publisher Statement
Copyright 2005 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
Citation Information
Peter Schwerdtfeger, Radovan Bast, Michael C.L. Gerry, Christoph R. Jacobs, et al.. "The quadrupole moment of the 3/2+ nuclear ground state of Au197 from electric field gradient relativistic coupled cluster and density-functional theory of small molecules and the solid state" The Journal of Chemical Physics Vol. 122 Iss. 12 (2005)
Available at: http://works.bepress.com/anja_mudring/54/