New evidence for a subshell gap at N=32

An 879.9(2) keV gamma -ray transition has been identified following the beta decay of V-58 and assigned as the 2(1)(+) --> 0(1)(+) transition in Cr-58(34). A peak in the energies of the first excited 2(+) slates for the even-even chromium isotopes is now evident at Cr-56(32), providing empirical evidence for a significant subshell gap at N = 32. The appearance of this neutron subshell closure for neutron-rich nuclides may be attributed to the diminished pi 1 f(7/2)-nu 1 f(5/2) monopole proton-neutron interaction as protons are removed from the 1 f(7/2) single-particle orbital. (C) 2001 Elsevier Science B.V. All rights reserved.