Highly deformed high-spin band in125I

Abstract

High-spin states in125 I have been investigated using the reaction 82 Se( 48 Ca,p4n) at a beam energy of 200 MeV and γ-ray coincidence events were detected using the Gammasphere spectrometer. A deformed rotational band, extending up to I π = 95/2 − , was observed for the first time in a heavier odd-A iodine nucleus. The characteristics of the band are very similar to those of the highly deformed bands observed recently in neighboring nuclei and it is 'identical' to one of the previously known bands in 126 Xe. The experimental results are compared to Cranked Nilsson-Strutinsky calculations and possible configurations for the band are discussed.

High-spin rotational bands in123I

“…Studies of neighboring nuclei [6][7][8][9][10] as well as the present calculations for 123 I, see below, indicate that the high-spin bands in the A 125 region are built on configurations with two proton holes in the g 9/2 subshell. Representative potential energy surfaces (PES) for such configurations with parity and signature (π, α) = (+, 1/2) are displayed in Fig.…”

“…These values were varied within reasonable limits to give agreement with theoretical predictions for the suggested configurations. The adopted values are similar to those of the connected bands in the neighboring nuclei 125 I [8], 125 Xe [9], and 126 Xe [10].…”

“…3. A comparison with the high-spin bands in the neighboring nuclei 120 Te [7], 125 I [8], and 125 Xe [9] demonstrates the similarity of their behavior. At high frequencies, abovehω = 0.95 MeV, the slopes of the curves for the 123 I bands change, however, not as drastically as for band L4 in 125 Xe.…”

“…The shape change is induced by the successive alignment of nucleons along the rotation axis and, finally, the level sequences terminate in maximally aligned oblate states [1][2][3][4][5][6]. In addition, several high-spin rotational bands have recently been observed in 120 Te [7], 124 Ba [6], 125 I [8], 125 Xe [9], and 126 Xe [10], which extend far beyond the noncollective oblate states. Only some of these sequences are firmly connected to lower-lying levels; they feed normal-deformed states in the spin range of I 25 at excitation energies around 10 MeV.…”

High-spin level scheme of doubly odd128I

“…The wide variety of structural features are naturally expected in the iodine isotopes with Z = 53; therefore experimental and theoretical efforts have been devoted to the iodine isotopic series during the past two decades [3][4][5][6]. Experimentally, both the I = 1 coupled bands built on the deformed 9/2 + proton-hole states and collective bands built on the low-lying πg 7/2 , πd 5/2 , and πh 11/2 intrinsic states have been systematically observed in the odd-A iodine nuclei [3,7,8].…”