Fission barriers of neutron-rich and superheavy nuclei calculated with the ETFSI method

Abstract Using the ETFSI (extended Thomas–Fermi plus Strutinsky integral) method, we have calculated the fission barriers of nearly 2000 exotic nuclei, including all the neutron-rich nuclei up to A=318 that are expected to be relevant to the r-process, and all superheavy nuclei in the vicinity of N=184 , with Z≤120 . Our calculations were performed with the Skyrme force SkSC4, which was determined in the ETFSI-1 mass fit. For proton-deficient nuclei in the region of N=184 we find the barriers to be much higher than previously believed, which suggests that the r-process path might continue to mass numbers well beyond 300. For the superheavy nuclei we typically find barrier heights of 6–7 MeV.

[1]  W. Loveland,et al.  Observation of Superheavy Nuclei Produced in the Reaction of K 86 r with P 208 b , 1999 .

[2]  J. Pearson,et al.  Thomas-Fermi approach to nuclear mass formula. (II). Deformed nuclei and fission barriers , 1987 .

[3]  J. Pearson,et al.  Hartree-fock calculations of semi-infinite nuclear matter with complete forces (finite-range and spin-orbit term)☆ , 1978 .

[4]  J. F. Wild,et al.  Synthesis of Superheavy Nuclei in the {sup 48}Ca + {number_sign}{sup 244}Pu Reaction , 1999 .

[5]  J. Pearson,et al.  Thomas-fermi approach to nuclear mass formula. (I). Spherical nuclei , 1986 .

[6]  M. Arnould,et al.  Waiting point approximation and canonical multi-event r-process revisited , 1996 .

[7]  W. Nazarewicz,et al.  Shell structure of the superheavy elements , 1996, nucl-th/9608020.

[8]  J. Pearson,et al.  Skyrme representation of a relativistic spin-orbit field , 1997 .

[9]  W. Myers,et al.  Nuclear ground state masses and deformations , 1995 .

[10]  S. Patel.  Extremes of nuclear structure , 1999 .

[11]  J. Pearson,et al.  Hartree-Fock calculations of surface-symmetry properties with finite-range forces , 1980 .

[12]  S. Goriely,et al.  Nuclear mass formula with Bogolyubov-enhanced shell-quenching: application to r-process , 1996 .

[13]  S. Goriely,et al.  Towards a Hartree-Fock mass formula , 2000 .

[14]  J. Pearson,et al.  Thomas-Fermi approach to nuclear mass formula: (III). Force fitting and construction of mass table , 1991 .

[15]  W. Myers,et al.  Nuclear properties according to the Thomas-Fermi model☆ , 1996 .

[16]  J. Pearson,et al.  Thomas-Fermi approach to nuclear-mass formula. (IV). The ETFSI-1 mass formula , 1992 .

[17]  C. Wagemans,et al.  Seminar on Fission: Pont D'Oye IV , 2000 .

[18]  B. Meyer.  The r-, s-, and p-Processes in Nucleosynthesis , 1994 .

[19]  A. P. Kabachenko,et al.  Synthesis of nuclei of the superheavy element 114 in reactions induced by 48Ca , 1999, Nature.

[20]  J. Pearson,et al.  Surface coefficients of Skyrme-Orsay forces , 1981 .

[21]  J. Pearson,et al.  Nuclear-matter symmetry coefficient and nuclear masses , 2000 .

[22]  W. M. Howard,et al.  Neutron-rich α-rich freeze-out and the r-process in the high-entropy neutrino-energized supernova bubble , 1993 .

[23]  W. M. Howard,et al.  Calculated fission barriers, ground-state masses, and particle separation energies for nuclei with 76 ≤ Z ≤ 100 and 140 ≤ N ≤ 184☆ , 1980 .

[24]  W. Myers,et al.  Thomas-Fermi fission barriers , 1999 .

[25]  W. Myers,et al.  Average nuclear properties , 1969 .

[26]  W. Greiner,et al.  Potential energy surfaces of superheavy nuclei , 1998, nucl-th/9902058.

[27]  R. Schaeffer,et al.  A Skyrme parametrization from subnuclear to neutron star densities Part II. Nuclei far from stabilities , 1998 .

[28]  J. W. Behrens,et al.  50 years with nuclear fission : National Academy of Sciences, Washington, D.C. and National Institute of Standards and Technology, Gaithersburg, Maryland, April 25-28, 1989 , 1989 .

[29]  J. Pearson,et al.  Nuclear mass formula via an approximation to the hartree-fock method , 1995 .

[30]  M. Rayet,et al.  Large-scale fission-barrier calculations with the ETFSI method , 1998 .

[31]  J. Pearson,et al.  Spin-orbit field and extrapolated properties of exotic nuclei , 1998 .

[32]  Pearson,et al.  Equation of state of homogeneous nuclear matter and the symmetry coefficient. , 1994, Physical review. C, Nuclear physics.