The 72 As nucleus was studied via the (␣,n␥) reaction at 14.2 MeV bombarding energy. Single ␥-, ␥␥-coincidence, and internal conversion electron spectra were measured with Ge͑HP͒ ␥-ray and superconducting magnetic lens plus Si͑Li͒ electron spectrometers. On the basis of the internal conversion coefficients of 72 As transitions, parities of the medium-spin levels up to 1.4 MeV excitation energy were determined, resulting in unambiguous parities also for the heads of the bands observed

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... The states observed were assigned to proton-neutron multiplets on the basis of their decay properties. The energy splittings of the observed multiplets are in accordance with the prediction of the previous interacting boson-fermion-fermion model ͑IBFFM͒ calculations using a transitional core lying between the vibrational SU͑5͒ and ␥-soft O͑6͒ limits, except that of the g 9/2 g 9/2 multiplet, which was described using the deformed SU͑3͒ core in the present IBFFM calculations. Such a core structure is in accordance with previous particle-rotor and Hartree-Fock-Bogoliubov calculations. ͓S0556-2813͑99͒03903-5͔ PACS number͑s͒: 21.10. Hw, 23.20.Lv, 21.60.Fw, 27.50.ϩe FIG. 2. The proposed level scheme for 72 As from the (␣,n␥) reaction up to 1.4 MeV excitation energy. Only levels with unambiguous parities and spin values Iу4 are presented. In addition to the energies of the ␥ rays, their multipolarities are also given. PRC 59 1329 FURTHER EVIDENCE ON SHAPE COEXISTENCE IN 72 As