The usual Hugenholtz-Van Hove theorem for a Fermi system is extended to describe asymmetric nuclear matter. It has been further developed to describe finite nuclei. It is shown that this extended relation could be used as a basis for a new mass relation which has both the liquid-drop and single-particle features. Its success in predicting masses of exotic neutron-rich nuclei is demonstrated.

• Received 20 June 1983

DOI:https://doi.org/10.1103/PhysRevLett.51.1243