Systematical calculations on superheavy nuclei
Sponsored Links
This presentation is the property of its rightful owner.
1 / 48

Systematical calculations on superheavy nuclei PowerPoint PPT Presentation


  • 69 Views
  • Uploaded on
  • Presentation posted in: General

Systematical calculations on superheavy nuclei. Zhongzhou REN Department of Physics, Nanjing University, Nanjing, China Center of Theoretical Nuclear Physics, National Laboratory of Heavy-Ion Accelerator, Lanzhou, China. Outline. Introduction

Download Presentation

Systematical calculations on superheavy nuclei

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Systematical calculations on superheavy nuclei

  • Zhongzhou REN

  • Department of Physics, Nanjing University, Nanjing, China

  • Center of Theoretical Nuclear Physics,

    National Laboratory of Heavy-Ion Accelerator,

    Lanzhou, China


Outline

  • Introduction

  • Nuclear structure calculations on superheavy nuclei (RMF, SHF, MM)

  • Alpha decay: density-dependent cluster model (DDCM)

  • Spontaneous Fission: new formula on half-lives of SF.

  • Summary


1. introduction: experiments

  • Z=110 (Ds), 111(Rg), 112 were produced at

    GSI, Hofmann, Muenzenberg…. Z. Phys. A, 1995-1996

  • Z=114-116, 118, at Dubna, by Oganessian et al….

    Nature, 1999; PRL. 1999;PRC, 2000-2005.

  • Z=110-111, new results, at Berkeley, PRL 2004….

  • Z=113, RIKEN, Morita,…, J. P. S. J., 2004.

  • 270Hs, Duellman, Turler, …, Nature 2003, EPJA 04.

  • 265Bh, Lanzhou, Gan, Qin, …, EPJA 2004.


1. introduction: theory.

  • J. A. Wheeler, 1950s: Superheavy nuclei

  • Werner and Wheeler, Phys. Rev., 109 (1958) 126.

  • 1960s-2000s, macroscopic-microscopic model (MM): Nilsson et al, Z=114 and N=184….

  • 1970s-2000s: Skyrme-Hartree-Fock (SHF) Model; Z=126? N=184?

  • 1990s-2000s: Relativistic Mean-Field model :

  • Z=120 ? N=184?

  • Spherical or deformed for superheavy nuclei ???


2. nuclear structure calculations

  • 2.1. RMF calculations on superheavy nuclei

  • Z=90-120:binding energies, deformations,…

  • Compare RMF with experimental data

  • RMF predictions on experiments

  • Ren et al. , PRC (2002-2005) ; NPA(2003-2005)…

  • 2. 2 New idea: shape coexistence and superdeformation

  • Ren and Toki, 2001, NPA, Ren et al,…

  • 2.3. Shape coexistence from other models

  • SHF model and MM model

  • Nature 433, 2005.

  • Atom. Data. Nucl. Data Tab. 77 (2001) 311 .


2.1 RMF results and discussion

  • Nuclei: Z =94—120; N=130—190.

  • Comparison of theoretical binding energy with exprimental data.

  • Comparison of theoretical alpha decay energy with exprimental data.

  • Comparison of theoretical quadrupole deformation with exprimental data.


Table 1, RMF results for Pu. (TMA and NLZ2). Experimental Beta2=0.29 for 238-244Pu.


Table 2, RMF results for Cm. (TMA and NLZ2)

Experimental deformation Beta2=0.30 for 244-248Cm


Table 5, RMF results for No. (TMA and NLZ2)

Experimental deformation Beta2=0.27 for 254No


Experimental B/A (MeV) is between two sets of RMF results (Z=98-108).


Fig. 3 Binding energy of the Z=112, A=277 alpha-decay chain from the RMF and Moller et al.


Fig. 4 Theoretical and experimental alpha decay energies for GSI Data: Z=110, 111, 112 ( +2, +1, 0 shift).


Tab. 10,results for Dubna data 292116. (TMA)(Beta2=0.46, 0.45,0.44 for SHF model.)


Tab. 11, results for Dubna data 292116. (NLZ2).(Beta2=0.46, 0.45,0.44 for SHF model).


2 new: shape coexistence,superdeformation

?Ren and Toki, Nucl. Phys. A 689 (2001) 691.

  • Z. Ren, Shape coexistence in even-even superheavy nuclei, Phys. Rev. C65, 051304 (2002)

  • Z. Ren et al., Phys. Rev. C66, 064306 (2002)

  • Z. Ren et al., Phys. Rev. C67, 064302 (2003)

  • Sharma, …,Munzenberg, PRC, 2005;

  • ..,Stevenson, Gupta, Greiner, JPG, 2006.

  • S. Goriely, F. Tondeur, J. Pearson, SHF Model

  • Atom Data and Nucl. Data Tables 77 (2001) 311.

  • Superdeformation for some superheavy nuclei


Fig. 9 Energy surface of Z=114, A=288.


15. Ren, Z. Shape coexistence in even-even superheavy nuclei. Phys. Rev. C65, 051304 (2002)

To be cited: shape coexistence, Ref. [15]

Nature, 433 (2005) 475


64. Z. Ren, Phys. Rev. C65, (2002) 051304(R) 65. Z. Ren et al., Phys. Rev. C66, (2002) 064306

Exp. Def. : 0.28, RMF Def.: 0.26-0.32,cited.


Z. Ren et al, PRC 67 (2003) 064302; NPA 722 (2003) 543.Prediction for 265107: Qa and Ta

Expt: Gan et al, EPJA 2004, Qa=9.24 , Ta=0.94 s.

Good agreement between theory and data.


Theoretical prediction: 265107 Qa and Ta Z. Ren et al, PRC 67 (2003) 064302; JNRS 3 (2002) 195.

Expt: Gan et al, EPJA 2004, Qa=9.38 , Ta=0.94 s.

Good agreement between theory and data.


Z. Ren, Prog. Theor. Phys. Supplement, No. 146 (2002) 498 (YKIS01, Japan).RMF prediction for 278113: Qa and Ta

Morita et al, JPSJ 2004, Qa=11.68, Ta=0.34 ms.

Good agreement between theory and data.


Oganessian et al, PRC72 2005

Predictions of SHF and RMF compare well with MM results [12,13]

南京大学


Oganessian et al, PRC72 2005

SHF [12,49-51] and RMF [13,52-57] compare well with the experimental results

南京大学


3. Density-Dependent Cluster Model

  • DDCM is a new model of alpha decay:

  • 1) effectve potential based on the Reid potential.

  • 2) low density behavior included.

  • 3) exchange included

  • 4) agreement within a factor of three for half-lives

  • Z Ren, C Xu, Z Wang, PRC 70: 034304 (2004)

  • C Xu, Z Ren, NPA 753: 174 (2005)

  • C Xu, Z Ren, NPA 760: 303 (2005)

  • C. Xu, Z. Ren, PRC 73: 041301(Rapid Commun.) (2006)


3. DDCM for alpha decay:agreement is within a factor of three for half-lives although experimental half-lives vary from 10-6 s to 1019 year


DDCM for superheavy nuclei (Z=106-118)


DDCM : 被PRC论文大段引用(共16处)

最近文献[7,16,18,28]研究了超重元素alpha衰变; 如图2为[7,18,28]的结果.我们的结果和[18]的结果基于不同的cluster模型.

文献[18]得到了超重核alpha衰变寿命好的符合.

文献[18]提出的结团模型理论很好描述了该区域.


DDCM: 被PRC论文大段引用(共16处)


Deformed DDCM: a spherical alpha-particle interacts with a deformed daughter nucleus with an axially symmetric deformation


The double-folding nuclear potential of 236U for two orientations, beta = 0◦ and beta = 90◦


In the multipole expansion, the density distribution of daughter nucleus is expanded as

The corresponding intrinsic form factor has the form

The double-folding potential can then be evaluated by a sum of different multipole components


The corresponding multipole components are

The polar-angle dependent penetration probability of alpha decay is given by

In the DDCM, thealpha-decay width has the following expression


The comparison of experimental alpha-decay half-lives and theoretical ones for even-even nuclei (Z= 52−104)


The distribution of the number of alphaemitters for different factors of agreement.


4. New formula of half-lives: Ground-State and isomer spontaneous fission.

  • Long lifetime line of G.S. fission: N=Z+52

  • Three formulas for G.S. fission.

  • New formula of fission half-lives of 33 isomers:

  • log10(T1/2) = -6 + c1(Z-92) + c2(N-Z-52)(N-146) + c3

  • C Xu, Z Ren, PRC 71: 014309 (2005)

  • Z Ren, C Xu, NPA 759: 64 (2005),….


Very good agreement for SF half-lives of isomers


Summary

  • Nuclear structure calculation :

  • Agreement with data and new predictions

  • Shape coexistence: isomers of superheavy nuclei; maybe superdeformation

  • More and more people agree since 2005.

  • Density-dependent cluster model of alpha decay (spherical and deformed)

  • New formulas for spontaneous fission:

  • Ground state and isomeric state


Thanks


国外同行对我们工作的引用和肯定


国内外同行对我们工作的引用和肯定


Geng, Toki, Zhao JPG 32 (2006) 573:超重核有形状共存, 大形变, 与我们结果一致.


编写电子和晕核散射新程序:相对论Eikonal近似

  • 1. 理论结果与现有实验数据非常符合

  • 2. 预言电子-丰质子核散射,能清楚探测质子晕 结构, 这是电子-质子晕核散射的第一个理论结果

  • 3. 为将来的电子-丰质子核对撞实验预研

  • 参考文献

  • Z Wang, Z Ren, PRC 70: 034303 (2004)

  • Z Wang, Z Ren, PRC 71: 054323 (2005)

  • ……


编写电子和晕核散射新程序:相对论Eikonal近似


  • Login