Binary-reaction spectroscopy ofMo99,100: Intruder alignment systematics inN=57<

Abstract

The near-yrast states of 99,100 Mo have been studied following their population via a binary reaction between a self-consistent, cranked-mean-field calculations using a Woods-Saxon potential. The alignment systematics of the intruder h 11/2 bands in the N=57 isotones from Mo ͑Z=42͒ to Cd ͑Z=48͒ and the yrast sequences in their N=58 even-even neighbors are discussed. An overall picture emerges, where the alignment properties evolve from being due to positive-parity neutrons in the 48 105Cd to predominantly ͑g 9/2 ͒ 2 proton crossings closer to the Z=40 subshell. Qualitatively, this can be explained by an increase in the quadrupole deformation and a simultaneous lowering of the proton Fermi surface in the g 9/2 shell with decreasing proton number. These data provide excellent examples of rotational-alignment phenomena in weakly deformed nuclei.

Electromagnetic properties of100Mo: Experimental results and theoretical description of quadrupole degrees of freedom

“…The level scheme of 100 Mo is well known from numerous studies of the γ radiation following the β decay of 100 Nb and reactions produced by light particles (n, p, d, α). The information on high spin states in 100 Mo was obtained in heavy-ion reactions induced by 136 Xe [5], 86 Kr [6], and 30 Si [7].…”

“…Contribution of the individual theoretical E2 matrix elements to the values of the Q 2 and Q 3 cos(3δ) invariants in 0 + 1 and 0 + 2 states of 100 Mo. The presented Q 3 cos(3δ) invariants, accordingly to the Eqs (5). and(6), result from the multiplication of the sum of all contributions by the factor (−1) ×35 2 × { } that is equal to −0.837.…”

Band mixing in 96,98Mo isotopes *

“…Small mixing pertains to small E0 strength in this nucleus. In heavy mass nuclei, the mixing configuration of members of the first two rotational bands in Sm is apparent [16]. In this case, the lower basis-state band is more collective than the second 100 94,96 98 band.…”

Magnetic moment of the 11/2− isomeric state in Mo99 and neutron spin g

“…The νh 11/2 intruder orbital defines the collective properties in this mass region. Regular sequences of γ rays which are built on the νh 11/2 orbital have been observed throughout the region [8][9][10][11][12][13]. In 99 Mo, a second microsecond isomeric level, located above the T 1/2 = 15.5 µs, J π = 5/2 + , E x = 97.785 keV one [14], at an excitation energy of E x = 684.10 keV was first observed by the work of Ref.…”

“…A spin and parity assignment was reported to be J π = 11/2 − [15,16], with an expected pure νh 11/2 configuration. The 99m2 Mo state has a weakly prolate shape and was identified as the head of the decoupled band associated with the population of the low-K components of the unique-parity νh 11/2 orbital [10,16]. The level scheme and decay path of the two isomers are presented in Fig.…”