Levels of 185Ir excited in the (α, x n) reactions

Evidence for shape coexistence in186Pt

“…The band 2 in 184pt shows a crossing with an alignment gain of A i~4 h due to i13/2 quasineutrons [4]. In 186pt the (vi~3/2) 2 crossing is absent in the prolate (+,0)o and (-, 1)2 bands as well as in all bands of lS5Ir [19] and 187Au [20].…”

“…A configuration assignment for the (+, 0)o band after the crossing can be obtained from blocking arguments considering the backbending behaviour of bands in the neighbouring nuclei 185pt [3], 18Sir [19] and 18VAu [20] as shown in Fig. 4b.…”

The asymmetric rotator model applied to odd-mass Iridium isotopes

“…Even more sophisticated developments, introducing the VMI prescription [16 18] or triaxiality of dynamical origin [19], were not able to give a coherent description of the three families of levels observed. Some interpretations [1,6,7,9] favour an axial assumption for the positive parity states; the h~1/2 system seems to suggest triaxiality [1,14] and it was hoped [6] that the h~, 2 levels could help to choose between this coexistence of forms. The different models which have been used start from very simple assumptions and introduce, initially, a limited (and reasonable) number of parameters.…”

“…c) negative parity states which are practically not connected with the preceeding ones and which arise from the h I 1/2 shell. Several attempts have been made to find some explanation for each of these systems of levels, among which one should mention -classical Coriolis coupling calculations [6,7,9] assuming a prolate axial deformation -coupling of an odd particle or hole to an asymmetric core [1,6]. This last approach was first suggested by Hecht and Satchler [12] and applied, with an isolated intrinsic configuration, to 191Ir, then developped for unique parity spectra by Meyer ter Vehn [13] who applied it [14] in particular to the h~1/2 levels in ~STIr.…”

“…Systematic experimental studies of odd mass Ir have recently been undertaken by complementary radioactivity studies [1-4, 10, 11] and in beam [5][6][7][8][9] experiments. These works have shown some specific features for which one has to find some coherent explanation.…”