A modified macroscopic-microscopic nuclear mass formula within considering isospin effect and continuum states

The coefficients of modified macroscopic-microscopic mass formula have been adjusted on 2267 experimental atomic masses extracted from the AME2012 atomic mass evaluation. Same as the Weizsäcker-Skyrme model the influence of the nuclear deformation on the macroscopic energy and the mirror nuclei constraint are also taken into account, and for the sake of the consistency of the model parameters between the macroscopic and the microscopic parts we approximate the isospin-dependent component of the macroscopic energy to the depth of the Woods-Saxon potential. Inspired by Kruppa prescription the continuum states are considered in the calculation of shell correction. Then the root-mean square (rms) deviation with respect to 2267 measured nuclear masses is 0.46 MeV. We predict the remaining 988 nuclei from the AME2012 with $Z,N>7$ for which the mass is still unknown or known with a higher uncertainty. In addition the α−decay energies of seven chains in the superheavy nuclei region with $Z=117,118$ are evaluated.