Experimental and theoretical studies of lifetimes and transition probabilities for AuII

Abstract

We report lifetime measurements for three of the 5d 9 6p levels in Au II and relativistic multiconfiguration Dirac-Fock (MCDF) calculations of lifetimes and transitions probabilities in this ion. The work was motivated by significant disagreements between previous experimental 5d 9 6p lifetimes, obtained by means of the beam-foil (BF) method and theoretical data based on Hartree-Fock calculations in which relativistic effects were included as perturbations. The new measurements, based on laser-induced fluorescence, support the BF data and are also in excellent agreement with the MCDF results. We confirm that, while computational methods which include perturbative relativistic corrections appear to be adequate for moderately heavy elements such as Ag, fully relativistic calculations are essential for describing systems as heavy as Au.

Transition probabilities and lifetimes in gold (Au I and Au II)

“…The Au II HFR lifetime values are reported in table 3 for the 5d 9 6p configuration. The theoretical results agree reasonably well with experiment (Beideck et al 1993, Zhang et al 2002, the only exception being the level at 85 708 cm −1 . For 76 660 cm −1 , the HFR value, in good agreement with the MCDF value, confirms the LIF measurements but not the BFS measurement.…”

“…normalized results (NORM) obtained using the laser-induced fluorescence lifetime measured in this work for 65 003.594 cm −1 , the laser lifetimes of Zhang et al (2002) for the levels at 63 053.318 and 76 659.700 cm −1 and the lifetime values of Beideck et al (1993) for the other levels (see the last column of table 3).…”

Experimental and theoretical transition probabilities for lines arising from the 6p configurations of Au II

“…As can be seen in table 1, there is a general good agreement between the present experimental probability values and the theoretical ones, especially with those calculated in this work and those reported by Zhiguo et al [25] and by Fivet et al [26]. Among the 16 listed transitions, more than 80% are best matched by our theoretical results.…”

“…There are also some published results of radiative lifetimes: Beideck et al [16] (relativistic Hartree-Fock and beam-foil excitation methods), Blagoev et al [24] (Hartree-Fock and delayed coincidence methods), Zhiguo et al [25] (multi-configuration Dirac-Fock calculations and the laser-induced fluorescence technique) and Fivet et al [26] (relativistic Hartree-Fock method).…”

“…Finally, as concerns transition probability values, calculations of these constants in Au II were reported in the latter three papers [24][25][26], in the works of Bogdanovich and Martinson [27] and in the aforementioned work of Rosberg and Wyart [19], where theoretical transition probabilities were calculated by superposition of the configuration approach and the Slater-Condon parametric method.…”