Nuclear electron captures and supernova explosion

(1)利用Wildenthal的有效相互作用，计算了全SHII模型组态下SD壳核在恒星物质中的弱相互作用率，考虑了最近广泛汇编的实验能级和Gamow-Tellerβ衰减率。在与Fuller、L、Newman(FFN)的计算结果进行比较的基础上，指出正确处理核结构效应是获得可靠的恒星物质弱相互作用率的关键。弱率与FFN的密度和温度网格点相同。(2)给出了大约30年前由Lialbleib和Sorensen首次提出的质子准粒子RPA模型的一个推广形式的综合表示。该模型使用可分离的Gamow-Teller公式，除了前一个模型的粒子-空穴力外，还包括粒子-粒子力，它对β^+衰变和ββ衰变具有绝对重要的作用。上述模型已进一步推广到奇奇核的处理。ALI推广也适用于核激发态的跃迁。这对于计算大质量恒星高温内部的核弱跃迁速率是至关重要的。补充了Lialbleib和Sorensen对粒子-空洞力的讨论，讨论了RPA色散关系的结构，重点讨论了粒子-粒子力的影响。

(1)The weak interaction rates in stellar matter are calculated for the sd shell nuclei in the full she II model configurations using the effective interaction of Wildenthal, taking into account the recent extensive compilations of experimental energy levels and Gamow-Teller beta deacay rates. Based on comparisons between the present calculation and that of Fuller, l'owler and Newman(FFN), it is pointed out that correct treatment of nuclear structure effect is decisive in order to get the reliable weak interaction rates in stellar matter. The weak rates are tabulated for the same grid points of density and temperature as those of FFN.(2)A comprehensive representation is presented of a generalized form of the protonneutron'quasiparticle RPA model, originally introduced by lialbleib and Sorensen almost thirty years ago. The model uses separable Gamow-Teller fores, including, in addition to the particle-hole force, of the former model, the particle-particle force, which is of deciive importance for beta^+ decay and beta beta decay. The above model has further been extended to the treatment of odd-odd nuclei. Ali extension is also made to transitions from nuclear excited states. This is essential for calculations of nuclear weak transition rates in the high-temperature interior of massive stars. Complementing the discussion of lialbleib and Sorensen on the particle-hole force, the structure of the RPA dispersion relation is discussed with emphasis on effects of the paricle-particle force.