In-gas-cell laser resonance ionization spectroscopy of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Ir</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>196</mml:mn><mml:mo>,</mml:mo><mml:mn>197</mml:mn><mml:mo>,</mml:mo><mml:mn>198</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>
M. Mukai, Y. Hirayama, Yutaka Watanabe, Sacha Schiffmann, J. Ekman, Michel Godefroid, P. Schury, Y. Kakiguchi, M. Oyaizu, M. Wada, Sohee Jeong, J. Y. Moon, J. H. Park, H. Ishiyama, Shin‐ichi Kimura, H. Ueno, M. Ahmed, Akira Ozawa, H. Watanabe, S. Kanaya, H. Miyatake
Abstract
Hyperfine structure (HFS) measurements of neutron-rich iridium isotopes $^{196,197,198}\mathrm{Ir}$ ($Z=77,\phantom{\rule{0.16em}{0ex}}N=119$--121) were performed via in-gas-cell laser resonance ionization spectroscopy at the KEK Isotope Separation System. Magnetic dipole moments $\ensuremath{\mu}$ and isotope shifts were determined from the HFS spectra. The variation of mean-square charge radii and quadrupole deformation parameters of these isotopes were evaluated from the isotope shifts. The $\ensuremath{\mu}$ value of $^{197}\mathrm{Ir}$ agreed with a theoretical value based on the strong coupling model, and the Ir nucleus was interpreted as prolately deformed by the theoretical calculations. The $\ensuremath{\mu}$ values of $^{196,198}\mathrm{Ir}$ were also compared with semiempirical values calculated based on the strong coupling model. From the comparison, we can suggest the possible spin values of ${I}^{\ensuremath{\pi}}=1,{2}^{\ensuremath{-}}$ for $^{196}\mathrm{Ir}$ and ${I}^{\ensuremath{\pi}}={1}^{\ensuremath{-}}$ for $^{198}\mathrm{Ir}$.