Complete-active-space multiconfiguration Dirac-Hartree-Fock calculations of hyperfine-structure constants of the gold atom

Abstract

The multiconfiguration Dirac-Hartree-Fock model has been employed to calculate the expectation values for the hyperfine splittings of the 5d 9 6s 2 2 D 3/2 and 5d 9 6s 2 2 D 5/2 levels of atomic gold. One-, two-, and three-body electron correlation effects involving all 79 electrons have been included in a systematic manner. The approximation employed in this study is equivalent to a complete-active-space approach. Calculated electric field gradients, together with experimental values of the electric quadrupole hyperfine-structure constants, allow us to extract a nuclear electric quadrupole moment Q͑ 197 Au͒ = 521.5͑5.0͒ mb.

Theoretical study of the hyperfine-interaction constants and the isotope-shift factors for the 3s21S0–3s3pZhang1, Xie2, Li3 et al. 2017Phys. Rev. A

“…It is worth noting that the higher-order correlation effects counteract the core-core correlation effects. [46,47], that is, the CC correlations always make the agreement worse between the calculated hyperfine interaction constants and the experimental values, and these discrepancies can be offset by the higher-order correlation. Hence, for the calculation asked for high precision, the CC correlation and the higher-order correlation are indispensable, which is also allowed us to evaluate the uncertainties in the calculation.…”

Collinear laser spectroscopy of atomic cadmium

“…Our computational models differ in the way the virtual orbitals are generated, as well as in the sets of CSFs in the wave function expansion (15); see Refs. [30,31] for further information. Below, we briefly refer to these models as single substitutions (S) and single with restricted double substitutions (SrrD and SrD); in some more detail, these models include:…”

“…The computational methodology of generating wave functions for hyperfine calculations have been explained elsewhere [29,30]. We shall describe here only the basics of the models which were applied in the three series of computations.…”

“…The size of the multi-configuration expansions is further restricted in this model by eliminating all CSF which do not interact with the reference CSF. Calculations based on an SrrD computational model have been found optimal for ab initio calculations of hyperfine structures in heavy atoms [30]. SrD The orbital sets as generated in the step SrrD above were utilized also for performing configuration-interaction calculations (i.e.…”

Accurate transition probabilities from large-scale multiconfiguration calculations - A tribute to Charlotte Froese Fischer

“…In this way values can be obtained also for very large systems. A typical example is given in [42], where the hyperfine structures of the 5d 9 6s 2 2 D 3/2 and 5d 9 6s 2 2 D 5/2 levels of atomic gold were estimated based on a number of multiconfiguration Dirac-Hartree-Fock calculations. Combined with the measured values of the hyperfine splittings the calculations were used to derive a new value of the nuclear quadrupole moment Q of 197 Au, with an error estimate.…”