Extending the nuclear chart by continuum：From oxygen to titanium

Nuclear masses ranging from O to Ti isotopes are systematically investigated with relativistic continuum Hartree-Bogoliubov（RCHB） theory, which can provide a proper treatment of pairing correlations in the presence of the continuum. From O to Ti isotopes, there are 402 nuclei predicted to be bound by the density functional PC-PK1. For the 234 nuclei with mass measured,the root mean square（rms） deviation is 2.23 MeV. It is found that the proton drip-lines predicted with various mass models are roughly the same and basically agree with the observation. The neutron drip-lines predicted, however, are quite diferent. Due to the continuum couplings, the neutron drip-line nuclei predicted are extended further neutron-rich than other mass models. By comparison with finite-range droplet model（FRDM）, the neutron drip-line nucleus predicted by RCHB theory has respectively2（O）, 10（Ne）, 10（Na）, 6（Mg）, 8（Al）, 6（Si）, 8（P）, 6（S）, 14（K）, 10（Ca）, 10（Sc）, and 12（Ti） more neutrons.