A consistent analysis of E2 transition probabilities for nine neutron-deficient even-even Se, Kr, and Sr isotopes has been performed, based on previous parametrizations for these nuclei within the proton-neutron interacting-boson model, from which boson effective charges ${\mathit{e}}_{\mathrm{\pi }}$ and ${\mathit{e}}_{\nu }$ are deduced. Two sets of effective charges are obtained, one set having ${\mathit{e}}_{\mathrm{\pi }}$≊${\mathit{e}}_{\nu }$ for most of the nuclei studied, and the other set having ${\mathit{e}}_{\mathrm{\pi }}$ substantially larger than ${\mathit{e}}_{\nu }$ for most of the nuclei. For both sets, ${\mathit{e}}_{\mathrm{\pi }}$ tends to decrease with increasing neutron number, while ${\mathit{e}}_{\nu }$ is roughly constant. More information on mixed-symmetry states is needed to determine which set is valid.

• Received 9 November 1989

DOI:https://doi.org/10.1103/PhysRevC.41.1762