Status of vibrational structure in 62Ni

Measurements consisting of gamma-ray excitation functions and angular distributions were performed using the (n, n'gamma) reaction on Ni-62. The excitation function data allowed us to check the consistency of the placement of transitions in the level scheme. From gamma-ray angular distributions, the lifetimes of levels up to similar to 3.8 MeV in excitation energy were extracted with the Doppler-shift attenuation method. The experimentally deduced values of reduced transition probabilities were compared with the predictions of the quadrupole vibrator model and with large-scale shell model calculations in the fp shell configuration space. Two-phonon states were found to exist with some notable deviation from the predictions of the quadrupole vibrator model, but no evidence for the existence of three-phonon states could be established. Z = 28 proton core excitations played a major role in understanding the observed structure.