SYSTEMATIC STUDY OF NUCLEAR BETA-DECAY

beta-decay properties of nuclei are studied in the framework of proton -neutron quasiparticle random-phase approximation with a schematic Gam ow-Teller residual interaction. Particle-hole and particle-particle te rms of the separable Gamow-Teller force are consistently included for both beta(+) and beta(-) directions, and their strengths are fixed as smooth functions of mass number A of nuclei in such a way that the cal culation reproduces observed beta-decay properties of nuclei. Using th e fixed interaction strengths, beta-decay half-lives of nuclei up to A = 150 are calculated, and generally good agreement with experiment is obtained. A schematic force which is relevant to the unique first-for bidden decay is also included in a similar way to the Gamow-Teller for ce, and its effects are studied.