Neutron-Proton pairing effect on the thermodynamical quantities of even-even proton-rich nuclei

Expressions of the thermodynamical quantities, i.e. the energy E, the entropy S and the heat capacity C are established by including the isovector neutron-proton (np) pairing effect. They are deduced using temperature-dependent gap equations. E, S and C are numerically studied as a function of the temperature for some even-even proton-rich nuclei. The single-particle energies used are those of a Woods-Saxon deformed mean field. It is shown that the isovector pairing effect on E, S and C is non-negligible, not only in the 0 <= T <= T-cnp region (T-cnp being the critical temperature beyond which the np pairing vanishes), but also in the T-cnp <= T <= T-cn region (T-cn being the neutron-system critical temperature).