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Effective quadrupole moments $q_{t,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ and $q_{22,\alpha}^{\mbox{\rm\scriptsize {eff}}}$

Figure 4: Experimental (closed symbols with error bars) and calculated (CRMF+NL1, open symbols) differential transition quadrupole moments for highly deformed bands in Ce, Pr, Nd, Pm, and Sm isotopes. The experimental data were taken from Refs. [21,20] and references quoted therein. The values of $\delta Q_t$ for SD band in $^{142}$Sm are shown in the inset. Dashed lines are drawn to guide the eye.
\includegraphics[width=13cm]{fig4.eps}

Table 2 displays the calculated effective s.p. transition quadrupole moments $q_{t,\alpha}^{\mbox{\rm\scriptsize {eff}}}$, cf. definitions (15-16). Based on the additivity principle, these values can be used to predict the total charge transition moments $Q_{t}(k)$ in highly deformed and SD bands of $A\sim130$ nuclei:

\begin{displaymath}
Q_{t}(k)=Q_{t}^{\mbox{\rm\scriptsize {core}}} + \sum_{\alpha}c_{\alpha}(k) q_{t,\alpha}^{\mbox{\rm\scriptsize {eff}}} ,
\end{displaymath} (30)

where the calculated CHF+SLy4 value for the core configuration in $^{131}$Cs is
\begin{displaymath}
Q_{t}^{\mbox{\rm\scriptsize {core}}} = 7.64\,\mbox{eb} .
\end{displaymath} (31)

Since the total calculated values are less precise than the relative ones which define the effective s.p. transition quadrupole moments $q_{t,\alpha}^{\mbox{\rm\scriptsize {eff}}}$, one may alternatively use in Eq. (30) the measured value [39],
\begin{displaymath}
Q_{t}^{\mbox{\rm\scriptsize {core,exp}}} = 7.4(3)\,\mbox{eb}.
\end{displaymath} (32)

Theoretical estimates of the total charge transition moments $Q_{t}(k)$ allow for predictions of $B(E2)$ values
\begin{displaymath}
B(E2)(I\rightarrow{I-2},k)= \frac{5}{16\pi} e^2 \langle I0\,20\vert I-2\,0\rangle Q^2_{t}(k),
\end{displaymath} (33)

and lifetimes [40].

In CHF+SLy4, the uncertainties of $q_{22,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ appear to be larger than those for $q_{20,\alpha}^{\mbox{\rm\scriptsize {eff}}}$. In CRMF+NL1, however, those uncertainties are similar. This can be traced back to the different $\gamma$-softness of potential energy surfaces in CHF+SLy4 and CRMF+NL1 (see Ref. [18] and references quoted therein for the results obtained in different approaches); current analysis revealing large uncertainties for $q_{22,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ suggests that the potential energy surfaces are softer (and, thus less localized) in the CHF+SLy4 approach.

Although the values of $q_{22,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ are generally much smaller than $q_{20,\alpha}^{\mbox{\rm\scriptsize {eff}}}$, large uncertainties in the determination of certain moments $q_{22,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ (especially, for $\nu [411]3/2^{\pm
i}$, $\nu [532]5/2^{\pm i}$, $\nu 6_3^{-i}$, $\pi [301]1/2^{+i}$, and $\pi [550]1/2^{-i}$ orbitals, for which the errors exceed 0.1eb in the CHF+SLy4 approach) can lead to the deterioration of predicted $q_{t,\alpha}^{\mbox{\rm\scriptsize {eff}}}$. On the other hand, in many cases the uncertainties in $q_{22,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ are smaller than the experimental error bars; hence, they are less relevant when comparison with experiment is carried out. Currently available experimental data on relative transition quadrupole moments agree reasonably well with the CHF+SLy4 results [21,20].

Table 2 compares $q_{t,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ values obtained in CHF+SLy4 and CRMF+NL1 models. The results for proton orbitals are similar in both approaches: the differences between respective $q_{t,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ values do not exceed 0.1eb. Larger differences are seen for the neutrons: for about 50 percent of calculated orbitals ( $\nu [402]5/2^{\pm i}$, $\nu [411]1/2^{\pm i}$, $\nu [411]3/2^{+i}$, $\nu [413]5/2^{-i}$, $\nu [530]1/2^{+i}$, and $\nu
[532]5/2^{+i}$), the difference between $q_{t,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ values in CHF+SLy4 and CRMF+NL1 exceeds 0.1eb. Interaction (mixing) between those close-lying states (see Fig. 2), predicted differently in the two approaches, is the most likely reason for the deviations seen.

The results of CHF+SLy4 were compared with experimental transition moments in Refs. [21,20]. Here, we show in Fig. 4 a comparison between CRMF+NL1 and experiment for the relative transition quadrupole moments $\delta Q_t(k)$ in different highly deformed and SD bands in nuclei with $Z$=57-62 involving $i_{13/2}$ neutrons and/or $g_{9/2}$ proton holes. The agreement between experiment and theory is quite remarkable with all the experimental trends discussed in Refs. [21,20] well reproduced by calculations. One should note that the CRMF and CHF results are close to each other. The general pattern of decreasing $Q_t$ with increasing $Z$ and $N$ is consistent with the general expectation that as one adds particles above a deformed shell gap, the deformation-stabilizing effect of the gap is diminished. This trend continues until a new ``magic'' deformed number is reached. Such a situation occurs when going from $^{132}$Ce towards $Z$=62 and $N$=80 ($^{142}$Sm), where a large jump in transition quadrupole moment takes place marking the point at which it becomes energetically favorable to fill the high-$j$ $\pi i_{13/2}$ and $\nu j_{15/2}$ orbitals responsible for the existence of the $A\sim
142$ SD island.

It is gratifying to see that CRMF+NL1 reproduces the value of $Q_t$ in $^{142}$Sm based on the $^{131}$Ce core (see inset in Fig. 4). Earlier on, it was demonstrated in Refs. [21,20,9] that this $Q_t$ value can be also reproduced within CHF using either a $^{131}$Ce or a $^{152}$Dy core.


Table: Effective s.p. charge quadrupole moments $q_{20,\alpha}^{\mbox{\rm\scriptsize{eff}}}$ and $q_{22,\alpha}^{\mbox{\rm\scriptsize{eff}}}$ as well as the transition quadrupole moments $q_{t,\alpha}^{\mbox{\rm\scriptsize{eff}}}$ (all in eb) calculated in CHF+SLy4 and CRMF+NL1.
   $±$     $±$     $±$    $±$     $±$     $±$ 
     $±$     $±$     $±$    $±$     $±$     $±$ 
State  CSHF + SLy4 CRMF + NL1 $±$     $±$     $±$ 
[ ${\cal N}n_z\Lambda$]$\Omega^r$   $q_{20,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ $q_{22,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ $q_{t,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ $q_{20,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ $q_{22,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ $q_{t,\alpha}^{\mbox{\rm\scriptsize {eff}}}$ $±$     $±$     $±$ 
$\nu$[402] $\frac{5}{2}^{+i}$  -0.35 $±$0.01  0.14 $±$0.06  -0.04 $±$0.04 -0.26 $±$0.02  -0.02 $±$0.01  -0.25 $±$0.02
$\nu$[402] $\frac{5}{2}^{-i}$  -0.34 $±$0.02  0.08 $±$0.08  -0.38 $±$0.05 -0.26 $±$0.02  -0.07 $±$0.02  -0.22 $±$0.03
$\nu$[411] $\frac{1}{2}^{+i}$  -0.15 $±$0.02  -0.24 $±$0.10  -0.01 $±$0.06 -0.11 $±$0.02  0.09 $±$0.02  -0.16 $±$0.02
$\nu$[411] $\frac{1}{2}^{-i}$  -0.12 $±$0.01  0.06 $±$0.06  -0.16 $±$0.04 -0.06 $±$0.02  -0.17 $±$0.02  0.04 $±$0.02
$\nu$[411] $\frac{3}{2}^{+i}$  -0.15 $±$0.04  0.20 $±$0.20  -0.26 $±$0.12 -0.13 $±$0.03  -0.02 $±$0.03  -0.11 $±$0.03
$\nu$[411] $\frac{3}{2}^{-i}$  -0.11 $±$0.05  -0.05 $±$0.24  -0.08 $±$0.15 -0.12 $±$0.03  0.02 $±$0.03  -0.12 $±$0.03
$\nu$[413] $\frac{5}{2}^{+i}$  -0.13 $±$0.02  -0.05 $±$0.10  -0.10 $±$0.06 -0.13 $±$0.03  -0.04 $±$0.03  -0.10 $±$0.03
$\nu$[413] $\frac{5}{2}^{-i}$  -0.12 $±$0.03  -0.12 $±$0.13  -0.05 $±$0.08 -0.11 $±$0.02  0.15 $±$0.03  -0.20 $±$0.03
$\nu$[523] $\frac{7}{2} ^{+i}$  0.03 $±$0.01  -0.00 $±$0.05  0.03 $±$0.03 0.05 $±$0.01  0.00 $±$0.01  0.04 $±$0.01
$\nu$[523] $\frac{7}{2} ^{-i}$  0.04 $±$0.01  -0.01 $±$0.05  0.05 $±$0.03 0.01 $±$0.02  -0.00 $±$0.02  0.01 $±$0.02
$\nu$[530] $\frac{1}{2}^{+i}$  0.22 $±$0.01  -0.21 $±$0.05  0.34 $±$0.03 0.17 $±$0.01  -0.09 $±$0.01  0.22 $±$0.01
$\nu$[530] $\frac{1}{2}^{-i}$  0.17 $±$0.01  -0.01 $±$0.05  0.18 $±$0.03 0.19 $±$0.01  0.10 $±$0.01  0.13 $±$0.01
$\nu$[532] $\frac{3}{2}^{+i}$  0.21 $±$0.03  0.21 $±$0.13  0.09 $±$0.08 -- -- --      $±$ 
$\nu$[532] $\frac{3}{2}^{-i}$  0.17 $±$0.03  0.03 $±$0.13  0.15 $±$0.08 -- -- --      $±$ 
$\nu$[532] $\frac{5}{2}^{+i}$  0.19 $±$0.03  -0.08 $±$0.20  0.24 $±$0.12 0.17 $±$0.03  -0.02 $±$0.03  0.18 $±$0.03
$\nu$[532] $\frac{5}{2}^{-i}$  0.24 $±$0.03  -0.01 $±$0.20  0.25 $±$0.12 0.38 $±$0.03  0.00 $±$0.03  0.38 $±$0.03
$\nu$[541] $\frac{1}{2}^{+i}$  0.35 $±$0.03  -0.04 $±$0.13  0.38 $±$0.08 0.35 $±$0.02  -0.00 $±$0.02  0.35 $±$0.03
$\nu$[541] $\frac{1}{2}^{-i}$  0.37 $±$0.03  0.01 $±$0.14  0.36 $±$0.08 0.33 $±$0.03  0.04 $±$0.03  0.30 $±$0.03
$\nu$ 6$_{1} ^{-i}$  0.38 $±$0.01  0.21 $±$0.03  0.26 $±$0.02 0.40 $±$0.01  0.12 $±$0.01  0.33 $±$0.01
$\nu$ 6$_{2} ^{+i}$  0.36 $±$0.01  -0.01 $±$0.04  0.37 $±$0.03 0.36 $±$0.01  -0.01 $±$0.01  0.37 $±$0.01
$\nu$ 6$_{3} ^{-i}$  0.35 $±$0.05  -0.06 $±$0.22  0.38 $±$0.13 -- -- --      $±$ 
$\pi$[301] $\frac{1}{2}^{+i}$  0.51 $±$0.05  -0.10 $±$0.24  0.57 $±$0.14 -- -- --      $±$ 
$\pi$[404] $\frac{9}{2}^{+i}$  -0.32 $±$0.01  0.10 $±$0.04  -0.38 $±$0.02 -0.37 $±$0.01  0.02 $±$0.01  -0.38 $±$0.01
$\pi$[404] $\frac{9}{2}^{-i}$  -0.32 $±$0.01  0.09 $±$0.04  -0.37 $±$0.02 -0.37 $±$0.01  0.02 $±$0.01  -0.38 $±$0.01
$\pi$[411] $\frac{3}{2}^{+i}$  -0.05 $±$0.02  0.10 $±$0.07  -0.10 $±$0.05 -- -- --      $±$ 
$\pi$[411] $\frac{3}{2}^{-i}$  0.00 $±$0.01  -0.22 $±$0.07  0.12 $±$0.04 -- -- --      $±$ 
$\pi$[422] $\frac{3}{2}^{+i}$  0.33 $±$0.02  -0.27 $±$0.10  0.48 $±$0.06 0.33 $±$0.03  -0.13 $±$0.02  0.40 $±$0.03
$\pi$[422] $\frac{3}{2}^{-i}$  0.34 $±$0.02  0.14 $±$0.10  0.25 $±$0.06 0.28 $±$0.02  0.16 $±$0.02  0.19 $±$0.02
$\pi$[532] $\frac{5}{2}^{+i}$  0.43 $±$0.01  -0.05 $±$0.05  -0.46 $±$0.03 0.41 $±$0.02  -0.04 $±$0.01  0.43 $±$0.02
$\pi$[532] $\frac{5}{2}^{-i}$  0.56 $±$0.03  -0.07 $±$0.09  0.60 $±$0.05 0.54 $±$0.03  0.05 $±$0.03  0.51 $±$0.04
$\pi$[541] $\frac{1}{2}^{-i}$  0.58 $±$0.02  -0.01 $±$0.10  0.59 $±$0.06 -- -- --      $±$ 
$\pi$[541] $\frac{3}{2}^{+i}$  0.50 $±$0.01  -0.05 $±$0.06  0.52 $±$0.04 0.48 $±$0.01  -0.10 $±$0.01  0.54 $±$0.01
$\pi$[541] $\frac{3}{2}^{-i}$  0.57 $±$0.01  -0.12 $±$0.04  0.63 $±$0.03 0.50 $±$0.01  -0.10 $±$0.01  0.56 $±$0.01
$\pi$[550] $\frac{1}{2}^{-i}$  0.49 $±$0.05  -0.06 $±$0.22  0.52 $±$0.14 0.47 $±$0.04  -0.02 $±$0.04  0.48 $±$0.04
   $±$     $±$     $±$    $±$     $±$     $±$ 


Table: Effective s.p. angular momentum alignments $j^{\mbox{\rm\scriptsize{eff}}}_{\alpha}$ (in $\hbar$) of the active orbitals calculated in CHF+SLy4 and CRMF+NL1. In the second column, the bare s.p. angular momenta $j^{\mbox{\rm\scriptsize{bare}}}_{\alpha}$, calculated with CHF+SLy4 are also shown.
    $±$    $±$ 
      $±$    $±$ 
State CHF+SLy4 CRMF+NL1 $±$ 
[ ${\cal N}n_z\Lambda$]$\Omega^r$ $j^{\mbox{\rm\scriptsize {bare}}}_{\alpha}$ $j^{\mbox{\rm\scriptsize {eff}}}_{\alpha}$ $j^{\mbox{\rm\scriptsize {eff}}}_{\alpha}$ $±$ 
$\nu$ [402] $\frac{5}{2}^{+i}$ $-$0.528 0.58 $±$0.14 0.47 $±$0.15
$\nu$ [402] $\frac{5}{2}^{-i}$ $-$0.493 0.51 $±$0.20 0.38 $±$0.26
$\nu$ [411] $\frac{1}{2}^{+i}$ 0.411 0.67 $±$0.24 0.64 $±$0.17
$\nu$ [411] $\frac{1}{2}^{-i}$ 0.380 0.40 $±$0.15 0.09 $±$0.16
$\nu$ [411] $\frac{3}{2}^{+i}$ $-$0.092 1.72 $±$0.46 1.35 $±$0.29
$\nu$ [411] $\frac{3}{2}^{-i}$ 0.077 0.56 $±$0.57 1.08 $±$0.29
$\nu$ [413] $\frac{5}{2}^{+i}$ $-$0.316 $-$0.10 $±$0.23 0.44 $±$0.27
$\nu$ [413] $\frac{5}{2}^{-i}$ $-$0.428 0.12 $±$0.30 0.14 $±$0.26
$\nu$ [523] $\frac{7}{2} ^{+i}$ $-$0.908 $-$1.10 $±$0.10 $-$1.24 $±$0.12
$\nu$ [523] $\frac{7}{2} ^{-i}$ $-$0.974 $-$1.19 $±$0.12 $-$0.92 $±$0.18
$\nu$ [530] $\frac{1}{2}^{+i}$ 1.548 1.19 $±$0.11 1.86 $±$0.09
$\nu$ [530] $\frac{1}{2}^{-i}$ 0.564 0.88 $±$0.11 0.93 $±$0.10
$\nu$ [532] $\frac{3}{2}^{+i}$ 0.171 $-$0.34 $±$0.30 --  
$\nu$ [532] $\frac{3}{2}^{-i}$ 0.835 0.44 $±$0.31 --  
$\nu$ [532] $\frac{5}{2}^{+i}$ $-$0.331 $-$0.89 $±$0.46 $-$0.95 $±$0.29
$\nu$ [532] $\frac{5}{2}^{-i}$ 0.417 $-$1.06 $±$0.46 $-$1.29 $±$0.30
$\nu$ [541] $\frac{1}{2}^{+i}$ 1.793 0.92 $±$0.31 0.95 $±$0.25
$\nu$ [541] $\frac{1}{2}^{-i}$ 0.466 0.89 $±$0.32 $-$0.34 $±$0.28
$\nu$ 6$_1^{-i}$ 4.840 4.78 $±$0.08 4.59 $±$0.08
$\nu$ 6$_2^{+i}$ 4.031 3.42 $±$0.11 3.15 $±$0.10
$\nu$ 6$_3^{-i}$ 2.662 0.77 $±$0.50 --  
$\pi$ [301] $\frac{1}{2}^{+i}$ $-$0.432 1.23 $±$0.55 --  
$\pi$ [404] $\frac{9}{2}^{+i}$ $-$0.719 $-$0.00 $±$0.09 0.09 $±$0.09
$\pi$ [404] $\frac{9}{2}^{-i}$ $-$0.719 $-$0.00 $±$0.09 0.11 $±$0.09
$\pi$ [411] $\frac{3}{2}^{+i}$ $-$0.249 0.81 $±$0.18 --  
$\pi$ [411] $\frac{3}{2}^{-i}$ $-$0.062 0.65 $±$0.16 --  
$\pi$ [413] $\frac{5}{2}^{-i}$ $-$0.539 $-$1.52 $±$0.53 --  
$\pi$ [422] $\frac{3}{2}^{+i}$ $-$0.315 $-$0.19 $±$0.25 $-$0.21 $±$0.27
$\pi$ [422] $\frac{3}{2}^{-i}$ 0.510 $-$0.84 $±$0.23 $-$0.38 $±$0.24
$\pi$ [532] $\frac{5}{2}^{+i}$ $-$0.253 $-$0.90 $±$0.13 $-$1.11 $±$0.16
$\pi$ [532] $\frac{5}{2}^{-i}$ $-$0.022 $-$0.67 $±$0.20 --  
$\pi$ [541] $\frac{1}{2}^{-i}$ 0.944 1.75 $±$0.23 --  
$\pi$ [541] $\frac{3}{2}^{+i}$ 1.743 1.57 $±$0.13 1.18 $±$0.11
$\pi$ [541] $\frac{3}{2}^{-i}$ $-$0.057 $-$0.54 $±$0.10 $-$0.48 $±$0.11
$\pi$ [550] $\frac{1}{2}^{-i}$ 2.819 2.99 $±$0.52 2.86 $±$0.40


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Next: Effective angular momenta (s.p. Up: Results of the additivity Previous: Effective charge quadrupole moments
Jacek Dobaczewski 2007-08-08