Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userYrast band in the heavy $N = Z$ nucleus $^{88}$Ru: $alpha$-cluster approach
74
0
0.0
(
0
)
Authors
Peter Mohr
Ask ChatGPT about the research
No Arabic abstract
The yrast band in the heavy $N = Z$ nucleus $^{88}$Ru is studied in the framework of the $alpha$-cluster model in combination with double-folding potentials. It is found that the excitation energies of the yrast band in $^{88}$Ru can be nicely described within the $alpha$-cluster approach using a smooth and mildly $L$-dependent adjustment of the potential strength. This result is similar to well-established $alpha$-cluster states in nuclei with a (magic core $otimes$ $alpha$) structure. Contrary, the yrast bands in neighboring $N e Z$ nuclei deviate from such a typical $alpha$-cluster behavior. Finally, the $alpha$-cluster model predicts reduced transition strengths of about 10 Weisskopf units for intraband transitions between low-lying states in the yrast band of $^{88}$Ru.
rate research
Read More
High spin states in the odd-odd N=Z nucleus 46V have been identified. At low spin, the T=1 isobaric analogue states of 46Ti are established up to I = 6+. Other high spin states, including the band terminating state, are tentatively assigned to the same T=1 band. The T=0 band built on the low-lying 3+ isomer is observed up to the 1f7/2-shell termination at I=15. Both signatures of a negative parity T=0 band are observed up to the terminating states at I = 16- and I = 17-, respectively. The structure of this band is interpreted as a particle-hole excitation from the 1d3/2 shell. Spherical shell model calculations are found to be in excellent agreement with the experimental results.
It has been debated whether the experimentally-identified superdeformed rotational band in $^{40}$Ar [E. Ideguchi, et al., Phys. Lett. B 686 (2010) 18] has an axially or triaxially deformed shape. Projected shell model calculations with angular-momentum-projection using an axially-deformed basis are performed up to high spins. Our calculated energy levels indicate a perfect collective-rotor behavior for the superdeformed yrast band. However, detailed analysis of the wave functions reveals that the high-spin structure is dominated by mixed 0-, 2-, and 4-quasiparticle configurations. The calculated electric quadrupole transition probabilities reproduce well the known experimental data and suggest a reduced, but still significant, collectivity in the high spin region. The deduced triaxial deformation parameters are small throughout the entire band, suggesting that triaxiality is not very important for this superdeformed band.
A highly-deformed rotational band has been identified in the N=Z nucleus 36Ar. At high spin the band is observed to its presumed termination at I=16+, while at low spin it has been firmly linked to previously known states in 36Ar. Spins, parities, and absolute excitation energies have thus been determined throughout the band. Lifetime measurements establish a large low-spin quadrupole deformation (beta_2=0.46+-0.03) and indicate a decreasing collectivity as the band termination is approached. With effectively complete spectroscopic information and a valence space large enough for significant collectivity to develop, yet small enough to be meaningfully approached from the shell model perspective, this rotational band in 36Ar provides many exciting opportunities to test and compare complementary models of collective motion in nuclei.
For more than half a century, the structure of $^{12}$C, such as the ground band, has been understood to be well described by the three $alpha$ cluster model based on a geometrical crystalline picture. On the contrary, recently it has been claimed that the ground state of $^{12}$C is also well described by a nonlocalized cluster model without any of the geometrical configurations originally proposed to explain the dilute gas-like Hoyle state, which is now considered to be a Bose-Einstein condensate of $alpha$ clusters. The challenging unsolved problem is how we can reconcile the two exclusive $alpha$ cluster pictures of $^{12}$C, crystalline vs nonlocalized structure. We show that the crystalline cluster picture and the nonlocalized cluster picture can be reconciled by noticing that they are a manifestation of supersolidity with properties of both crystallinity and superfluidity. This is achieved through a superfluid $alpha$ cluster model based on effective field theory, which treats the Nambu-Goldstone zero mode rigorously. For several decades, scientists have been searching for a supersolid in nature.Nuclear $alpha$ cluster structure is considered to be the first confirmed example of a stable supersolid.
$alpha$-decay always has enormous impetuses to the development of physics and chemistry, in particular due to its indispensable role in the research of new elements. Although it has been observed in laboratories for more than a century, it remains a difficult problem to calculate accurately the formation probability $S_alpha$ microscopically. To this end, we establish a new model, i.e., multistep model, and the corresponding formation probability $S_alpha$ values of some typical $alpha$-emitters are calculated without adjustable parameters. The experimental half-lives, in particular their irregular behavior around a shell closure, are remarkably well reproduced by half-life laws combined with these $S_alpha$. In our strategy, the cluster formation is a gradual process in heavy nuclei, different from the situation that cluster pre-exists in light nuclei. The present study may pave the way to a fully understanding of $alpha$-decay from the perspective of nuclear structure.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
