The Skyrme interaction and the related arguments

Last modification: 1996/3/25
The relation between the Skyrme-HF model and the relativistic mean-field model [Re89] has been discussed by many authors (see, e.g., Ref. [SHT93]), which has invoked arguments on the density dependence (the ratio of the isoscalar to the isovector density dependences) of the spin-orbit term [SLH94,DN94,PF94,RF94]. However, as these arguments are not yet conclusive, we rather like to use the old but well-examined standard form of the Skyrme force in this paper.

Among the many parameter sets proposed for the Skyrme force [APD92,DFT84,BFG75,Koe76,KTO80,GS81,BQB82,WHW83,GPN92], we choose the SIII [BFG75]. Its validity has been examined in many nuclear structure calculations. In particular, it produces single-particle spectra in good agreement with experiment. It also reproduces fairly well the N-Z dependence of the binding energy [TBF93] compared with other widely-used parameter sets of SGII [GS81] and SkM* [BQB82]. Although its incompressibility is said to be too large, it is not a serious drawback because elaborate fittings of the parameters of the Skyrme force [RF94] and the FRDM [MNM94] have shown that different assumptions for the incompressibility lead to practically the same quality of fittings to nuclear masses.

The force SkSC4 [APD92] was determined through the most extensive fitting to nuclear mass data among the Skyrme forces. It is not our intention to criticize the force, but it should be noticed that the fitting was done in the ETFSI scheme, which produces unnegligibly different energy from that of the HF method. Because of this disadvantage, we do not choose the force SkSC4 in this paper. In future calculations, this force is certainly one of the important forces to be tried.