Collectivity evolution in the neutron-rich Pd isotopes toward the N=82 shell closure

The neutron-rich, even-even Pd-122,Pd-124,Pd-126 isotopes were studied via in-beam gamma-ray spectroscopy at the RIKEN Radioactive Isotope Beam Factory. Excited states at 499(9), 590(11), and 686(17) keV were found in the three isotopes, which we assign to the respective 2(1)(+) -> 0(gs)(+) decays. In addition, candidates for the 4(1)(+) states at 1164(20) and 1300(22) keV were observed in Pd-122 and Pd-124, respectively. The resulting E-x(2(1)(+)) systematics are similar to the Xe (Z = 54) isotopic chain and theoretical predictions by the proton-neutron interacting boson model (IBM-2), indicating the magic nature of N = 82 in the Pd isotopes.