973 工作匯報(bào) 任中洲 南京大學(xué)物理系

1、Systematical calculations on superheavy nuclei,Zhongzhou RENDepartment of Physics, Nanjing University, Nanjing, ChinaCenter of Theoretical Nuclear Physics, National Laboratory of Heavy-Ion Accelerator, Lanzh

2、ou, China,Outline,IntroductionNuclear 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. int

3、roduction: experiments,Z=110 (Ds), 111(Rg), 112 were produced at GSI, Hofmann, Muenzenberg…. Z. Phys. A, 1995-1996Z=114-116, 118, at Dubna, by Oganessian et al…. Nature, 1999; PRL. 1999;PRC, 2000-2005.

4、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. W

5、heeler, 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=12

6、6? 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：

7、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

8、 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

9、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 defo

10、rmation 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

11、 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 cha

12、in 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

13、 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 eve

14、n-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, 20

15、06.S. Goriely, F. Tondeur, J. Pearson, SHF ModelAtom 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 ev

16、en-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

17、,,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 agreemen

18、t 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 the

19、ory 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 agreemen

20、t between theory and data.,南京大學(xué),,,Predictions of SHF and RMF compare well with MM results [12,13],,Oganessian et al, PRC72 2005,南京大學(xué),,,SHF [12，49-51] and RMF [13，52-57] compare well with the experimental results,,,Ogane

21、ssian et al, PRC72 2005,3. 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 included4) agreement w

22、ithin a factor of three for half-livesZ 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

23、 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論文大段引用(共16處),,,最近文獻(xiàn)[7,16,18,28]研究了超重元素alpha衰

24、變; 如圖2為[7,18,28]的結(jié)果.我們的結(jié)果和[18]的結(jié)果基于不同的cluster模型.,,文獻(xiàn)[18]得到了超重核alpha衰變壽命好的符合.,,文獻(xiàn)[18]提出的結(jié)團(tuán)模型理論很好描述了該區(qū)域.,DDCM: 被PRC論文大段引用(共16處),,Deformed DDCM: a spherical alpha-particle interacts with a deformed daughter nucleus with an

25、 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 corre

26、sponding 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 p

27、robability of alpha decay is given by,In the DDCM, the alpha-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 distri

28、bution of the number of alpha emitters 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+52Three formulas for G.S. fi

29、ssion.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

30、of isomers,Summary,Nuclear structure calculation :Agreement with data and new predictionsShape coexistence: isomers of superheavy nuclei; maybe superdeformationMore and more people agree since 2005.Density-depe

31、ndent cluster model of alpha decay (spherical and deformed) New formulas for spontaneous fission:Ground state and isomeric state,Thanks,國(guó)外同行對(duì)我們工作的引用和肯定,國(guó)內(nèi)外同行對(duì)我們工作的引用和肯定,Geng, Toki, Zhao JPG 32 (2006) 573:超重核有形狀共存,

32、大形變, 與我們結(jié)果一致.,,編寫電子和暈核散射新程序：相對(duì)論Eikonal近似,1. 理論結(jié)果與現(xiàn)有實(shí)驗(yàn)數(shù)據(jù)非常符合2. 預(yù)言電子-豐質(zhì)子核散射,能清楚探測(cè)質(zhì)子暈 結(jié)構(gòu), 這是電子-質(zhì)子暈核散射的第一個(gè)理論結(jié)果3. 為將來(lái)的電子-豐質(zhì)子核對(duì)撞實(shí)驗(yàn)預(yù)研參考文獻(xiàn)Z Wang, Z Ren, PRC 70: 034303 (2004)Z Wang, Z Ren, PRC 71: 054323 (2005)……,編寫電子和暈