Shape coexistence in odd-mass Au isotopes: Determination of the excitation energy of the lowest intruder state in 179Au
Venhart, Martin × Andreev, Andrei Wood, J.L. Antalic, S. Bianco, L. Greenlees, P.T. Jakobsson, U. Jones, P. Julin, R. Juutinen, S. Ketelhut, S. Leino, M. Nyman, M. Page, R.D. Peura, P. Rahkila, P. Sarén, J. Scholey, C. Sorri, J. Thomson, J. Uusitalo, J. #
Physics Letters B vol:695 issue:1-4 pages:82-87
Phenomenon of the shape coexistence has been investigated in 179Au. This very neutron-deficient isotope, 18 neutrons away from the stable gold isotope 197Au, was studied by a combination of α-decay and isomer-decay spectroscopy employing the ritu gas-filled separator and the great focal-plane spectrometer at the University of Jyväskylä. A new isomer with t1/2 = 328(2) ns was observed and states associated with π(d3/2)^-1, π(s1/2)^-1, π(f7/2)^+1 and π(h9/2)^+1 structures were revealed. The implications of these results on the systematics of π(h9/2)^+1 and π(f7/2)^+1 intruder structures in the odd-mass gold isotopes are discussed. The minimum of the parabolic trend is at N = 104, i.e. exactly at the mid-shell point and the π(f7/2)^+1 structure is dropping in energy relative to the π(h9/2)^+1 with decreasing mass number.