The role of configuration mixing in the Pt region is investigated. For this
chain of isotopes, the nature of the ground state changes smoothly, being
spherical around mass A∼174 and A∼192 and deformed around the
mid-shell N=104 region. This has a dramatic effect on the systematics of the
energy spectra as compared to the systematics in the Pb and Hg nuclei.
Interacting Boson Model with configuration mixing calculations are presented
for gyromagnetic factors, α-decay hindrance factors, and isotope shifts.
The necessity of incorporating intruder configurations to obtain an accurate
description of the latter properties becomes evident.Comment: Accepted in Physical Review