Nuclear Structure Studies with Pick-up Reactions on Even Tellurium Nuclei: The¹²⁶Te (d,t)¹²⁵Te and the¹²⁶Te (³He,α)¹²⁵Te Reactions

Abstract

The level structure of 125Te up to an excitation energy of ∼ 2.2 MeV has been investigated by the (d, t) and (3He, α) reactions with beams of 17 MeV deuterons and 24 MeV 3He particles. Angular distributions were recorded and analyzed with standard DWBA calculations. Spectroscopic factors were deduced. Anomalous angular distributions and cross sections of some low-lying and weakly excited positive parity states are explained using CCBA calculations. A new level, probably ½+, is observed at 538 keV.

Beta decay of 125Sb and level structures in 125Te

“…Based on systematics, Walters and Meyer [13] placed this level at approximately 560 keV and accordingly searched the Compton suppression spectra in the 515-535 keV region to look for its decay gamma-ray to the 35 keV level; no positive evidence for any 1/2 · level at (560 ¦ 10) keV could result from this search. Later, the single-particle transfer reaction studies of Rodland et al [27] In view of these results, and the Á ¼ character from´ ص study [27], we introduce the 538.61 keV 1/2 · level in our level scheme of figure 3. at 652.87 keV respectively to the 1/2 · ground state, 35.49 keV 3/2 · , 321.07 keV 9/2 and 443.56 keV 3/2 · levels.…”

“…The extraordinary lowering of Á ½ states and Á ¾ states, where is a unique parity orbital, could be understood through cluster model calculations [31] which incorporate dressed ¿Õ Ôand ÕÔclusters. In this picture, discussed in detail by Rodland et al [27], these so-called anomalous coupling (AC) states are regarded as manifestations of ¿Õ Ôand ÕÔ modes which, under the special shell structure conditions, may be regarded as 'elementary modes', breaking the QPC picture. Accordingly, the 321 keV 9/2 state is ½¾ Te is viewed as ¿Õ Ôconfiguration.…”

“…A low-lying ½ ¾ · state, expected from systematics and also from theoretical considerations, is indicated around 538 keV from single-particle transfer reaction studies [27], but it still remains unobserved in decay or any other studies [1,13]. Also, the possible existence of 402 keV and 653 keV levels, tentatively proposed in early decay studies [4][5][6]9], was not confirmed in later experiments [1].…”

“…Detailed information on the level structures upto excitation energy of 700 keV has been sought through gamma-ray and conversion electron spectroscopy following beta decay of the long-lived (Ø ½ ¾ = 2.76y) source ½¾ Sb [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Supporting information, albeit with lesser precision, over this region has come from a variety of other techniques [1,2,[23][24][25][26][27][28], e.g. ½¾ I EC decay, radiative neutron capture, Coulomb excitation,´« ÜÒµ in-beam experiments, particle transfer reaction studies etc.…”