Shell model study of high spin states in theN=50 nucleus93Tc

Abstract

Abstract. High spin states in the N = 50 nucleus 93Tc were reinvestigated by using the reaction 64Zn (35C1, 4p 2 n) at a beam energy of 140 MeV. This was done particularly with a view to observe any 7 rays upto 2.7 MeV which may have been missed in our earlier study where the experimental conditions were set to observe 7 rays upto 2 MeV. We found four new 7 rays of energy: 2484, 2164, 2130 and 69 keV. We have placed these ,/rays in the level scheme and it now gets extended to 49/2-. Though there is no substantial change in the level scheme, placing the 7 rays in the level scheme has resulted into two important conclusions: (1) We have performed shell model calculations for 93Tc nucleus within a model space which encompasses an enlarged proton configuration and allows for the excitation of the neutron across the N = 50 core. The excitation of a single neutron across the N = 50 core satisfactorily explains the new level scheme. (2) The energy of the 17/2 isomeric state is now unambiguously placed at 2185 keV.

Investigation of the level structure of 90Nb nucleus using the shell model

“…The single particle energies (SPEs) corresponding to the model space are set as the same in Refs. [7,14,15]:…”

Multi-quasiparticle excitations and the impact of the high-j intruder orbital in the N = 51 93Mo nucleus *

“…The level structures of nuclei near the Z = 38 semimagic and N = 50 magic shells have been the focus of experimental and theoretical research in recent years [1][2][3][4][5][6][7][8][9]. A number of interesting phenomena, such as single-particle excitation [3][4][5][6][7][8], isomeric states [8][9][10][11][12], collective rotation [13,14], and core breaking [15][16][17][18], have been reported in this mass region. The level structures of Zr, Nb, and Tc isotones around have been extended to higher spins and are well described by the shell model [16][17][18][19].…”

“…Large scale shell model calculations that account for these orbitals were therefore performed to investigate the origin and components of the excited states in Mo. Moreover, although Mo has been observed up to higher excitation energies of approximately 10 MeV [9], due to the limitations of the experimental conditions, the spin-parity assignments of the higher-lying states remain indefinite. It was thus necessary to predict the multipolarities of the higher-spin states in Mo theoretically.…”

“…2, respectively, in comparison with the experimental values taken from Refs. [9,25,26] . As evident in Figs.…”

High-spin states inTc94and the shell-model interpretation

“…A truncation scheme had, therefore, to be devised to make these calculations feasible; the details of this procedure are described in Refs. [15,16]. Calculations were performed within a model space which had Ni as the core, and the~( 0fs/2, 1ps/2, lp, /2, Ogs/2) and v(lp, /2, Ogs/2, Og7/2 lds/2, 1ds/2, 2sz/2) orbits.…”