Levels inZr90: Theoretical

Abstract

An attempt is made to describe the seven levels of Zr 90 below 3.6 Mev in terms of the proton configurations (2pi/2) 2 , (2pi/21^9/2), and (lgg/2) 2 . The level positions and the compositions of the two 0+ states are determined for Gaussian and Yukawa forces of various ranges and exchange characters. The experimental data are well reproduced for a reasonable choice of the force parameters, the best fit being obtained with a Serber exchange mixture and a range of about 1.5 fermis. The experimental values of the half-lives of the excited states can also be reconciled with these simple configurational assignments. The most serious discrepancy is in the half-life of the first excited (0+) state, which we calculate to be 1.35X10" 8 sec, as compared to the observed value of (6.0=hl.5)X10 -8 sec. The remaining discrepancies in the energies and half-lives are in the direction of the effects produced by a slight deformation of the Sr 88 core.

Experimental Study of theT=TzStates inZr90<

“…and the first three low-lying states in 90 Zr have previously been investigated, 12,13 and since our results are in good agreement with the previous results, additional discussion is not necessary.…”

“…These parameters were obtained from a systematic analysis of the deuteron opticalmodel interactions in the range of Ed- [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] MeV which shows that, for fixed geometrical parameters, there is a smooth variation of V and W with energy.…”

Structure of excited states in Se-isotopes

“…Another striking characteristic is the behaviour of B(E2) values between the 0 +' states and the first excited 2~ states: The B(E2) values is strongly enhanced at N =40 getting smaller as the neutron number increases, and becomes quite small for the N=46 isotope in comparison with the value predicted by the simple phonon model. An explanation for the anomalous 0 +' first excited state in V2Ge has been suggested by Monahan et al [-3] in terms of a (2pl/2)2= o and (1 g9/2)2= 0 pair configuration mixture for the last two neutrons in analogy to the work of Bayman et al [4]. In the case of 72Ge, however, this explanation is not consistent with the observed B(E2: 0+'+2~ -) value, which strongly suggests that these two states are still members of a collective family in spite of their notable deviations in energy from the simple phonon model.…”

Energy levels of 98Mo excited in the (n, γ) reaction

“…Hs occurrence is assigned to a proton configuration composed of 37 % (2Pt)2 and 63 % (1g t )2 [ref. 43)]. In 98Mo with 42 protons two similar orthogonal configurations of…”