We have used an electron-beam ion trap to measure the wavelength of the $J=2\mathrm{}–3$ magnetic dipole transition in the ${3d}^4$ ground term of Ti-like ytterbium, tungsten, and bismuth. This fills in a gap in previous measurements along this isoelectronic sequence, as well as extending previous work to the highest Z yet. With the addition of our results, measurements of this line now cover a sufficient range of Z to allow an interpolation of reliable wavelength estimates for the unmeasured members of the isoelectronic sequence from $Z=52\mathrm{}$ to 83. We provide a table of these wavelengths for each member of the sequence in this range, and compare the measured wavelengths to recent calculations. Our results show that a long-standing discrepancy between prediction and experiment disappears in the high-$Z$ limit.

• Received 24 September 1999

DOI:https://doi.org/10.1103/PhysRevA.61.054501