Similarly, the extrapolation ability of the RBF approach in the superheavy region is investigated. Figure
4 shows the deviations between the evaluated masses from AME2016 and masses extrapolated by the DZ31 and HFB27 models and their corresponding improved masses extrapolated by the RBF approach. Figure
4(a) shows the results of the DZ31 model and the DZ31+RBF for nuclei with proton numbers
Z = 106–118. It can be seen that the deviations between the predicted results of the DZ31 model and the evaluation masses from AME2016 are more than 6 MeV, but the results of the DZ31+RBF model are reduced to 3 MeV. Figure
4(b) shows the results of the DZ31 and DZ31+RBF models for nuclei with proton numbers
Z = 111–118. It is found that the results after 3 steps of extrapolation are worse than the results in figure
4(a), even though the learning set is expanded. Figure
4(c) shows the results of the HFB27 and HFB27+RBF models for nuclei with proton numbers
Z = 106–118. Although the extrapolation results of the HFB27 model combined with the RBF approach achieve good results within five steps, the extrapolation results beyond five steps are worse than those of the HFB27 model alone. As can be seen from figure
4(d), although the learning set is expanded, the extrapolated results of the HFB27+RBF model are worse than those of figure
4(c). It can be seen that, based on the information obtained from figure
4, the RBF approach should be carefully combined with the DZ31 and HFB27 models when extrapolating nuclear masses in the superheavy region. Figure
5 shows the deviations between the evaluation masses from AME2016 and the masses extrapolated using the WS4 and FRDM12 models and their corresponding improved masses extrapolated by the RBF approach. Figure
5(a) shows the results of the WS4 and WS4+RBF models for nuclei with proton numbers
Z = 106–118. It is found that the extrapolation results of the WS4 model are significantly improved by the RBF approach. It is worth mentioning that in figure
5(b), the extrapolation results of the WS4 model will be further improved by the RBF approach due to the expansion of the learning set. The deviations between the evaluation masses from AME2016 and the masses extrapolated by the WS4 model combined with the RBF approach are within 1 MeV for nuclei with proton numbers
Z = 111–118. Figures
5(c) and (d) show the results of the FRDM12 and FRDM12+RBF models. The trends of their results are similar to those of the WS4 model. It is found that, by studying the distribution of the deviation between the evaluation masses from AME2016 and prediction results of the models, the deviations of the nuclides near
Z = 114, compared to those of the nuclides near
Z = 110, showed a larger mutation for the DZ31 and HFB27 models. This may be the reason for the reversal of the prediction results of the DZ31 and HFB27 models combined with the RBF approach in the superheavy region.