The influence of binding energies of electrons on nuclear mass predictions

Jing Tang, Zhong-Ming Niu, Jian-You Guo

Published 2015-11-26Version 1

Nuclear mass contains wealth of nuclear structure information, and it has been widely employed to extract the nuclear effective interactions. The known nuclear mass is usually extracted from the experimental atomic mass by subtracting the masses of electrons and adding the binding energy of electrons in atom. However, the binding energies of electrons are sometimes neglected in extracting the known nuclear masses. The influence of binding energies of electrons on nuclear mass predictions are carefully investigated in this work. It is found that the rms deviations of nuclear mass predictions with respect to the known data are increased about $200$ keV for nuclei with $Z, N\geqslant 8$, if the binding energies of electrons are directly subtracted from the theoretical mass predictions. Furthermore, by using the Coulomb energies among protons to absorb the binding energies of electrons, whose influence on the rms deviations is significantly reduced with only about $10$ keV for nuclei with $Z, N\geqslant 8$. However, the binding energies of electrons are still important for the heavy nuclei, which are about $150$ keV for nuclei around $Z=100$ and go up to about $500$ keV for nuclei around $Z=120$. Therefore, it is necessary to consider the binding energies of electrons for reliably predicting the masses of heavy nuclei with an accuracy of about hundreds of keV.