Relativistic quasiparticle time blocking approximation: Dipole response of open-shell nuclei
Relativistic quasiparticle time blocking approximation: Dipole response of open-shell nuclei
复制标题
相对论准粒子时间阻塞近似：开壳核的偶极子响应
DOI：
10.1103/physrevc.78.014312
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发表时间：
2008
影响因子：
3.1
通讯作者：
V. Tselyaev
中科院分区：
文献类型：
--
作者：
E. Litvinova;P. Ring;V. Tselyaev
利用准粒子时间阻塞近似（QTBA）建立了准粒子-声子耦合（QPC）模型，推广了自洽的相对论准粒子无规相近似（RQRPA）。该方法是制定在Bethe-Salpeter方程（BSE）在两个准粒子空间与能量依赖的两个准粒子的剩余相互作用。这个方程可以在形成基态自洽解的狄拉克态的基础上求解，也可以在动量表象中求解。配对的相关性内的Bardeen-Cooper-Schrieffer（BCS）模型中处理的一个Escherole-Schrieffer相互作用。相同的NL 3组耦合常数产生的Dirac-Hartree-BCS单准粒子谱，剩余的两个准粒子相互作用和准粒子-声子耦合振幅的静态部分。在此框架下，对质量数A= 100，106，114，116，120和130的锡同位素链（Z=50）和（N=50）{sup 88}Sr，{sup 90}Zr，{sup 92}Mo同位素链中的电偶极激发进行了定量描述.扩展的RQRPA耦合到集体振动产生的光谱与众多的2 q x声子（两个准粒子加声子）的状态提供了一个显着的破碎的巨偶极共振以及软偶极模式（pygmy共振）在调查中的核。获得的光吸收更多»横截面和计算的偶极谱的低位置强度的积分贡献的结果与现有的实验数据非常一致。«少
The self-consistent relativistic quasiparticle random-phase approximation (RQRPA) is extended by the quasiparticle-phonon coupling (QPC) model using the quasiparticle time blocking approximation (QTBA). The method is formulated in terms of the Bethe-Salpeter equation (BSE) in the two-quasiparticle space with an energy-dependent two-quasiparticle residual interaction. This equation is solved either in the basis of Dirac states forming the self-consistent solution of the ground state or in the momentum representation. Pairing correlations are treated within the Bardeen-Cooper-Schrieffer (BCS) model with a monopole-monopole interaction. The same NL3 set of the coupling constants generates the Dirac-Hartree-BCS single-quasiparticle spectrum, the static part of the residual two-quasiparticle interaction and the quasiparticle-phonon coupling amplitudes. A quantitative description of electric dipole excitations in the chain of tin isotopes (Z=50) with the mass numbers A=100,106,114,116,120, and 130 and in the chain of isotones with (N=50) {sup 88}Sr, {sup 90}Zr, {sup 92}Mo is performed within this framework. The RQRPA extended by the coupling to collective vibrations generates spectra with a multitude of 2q x phonon (two quasiparticles plus phonon) states providing a noticeable fragmentation of the giant dipole resonance as well as of the soft dipole mode (pygmy resonance) in the nuclei under investigation. The results obtained for the photo absorptionmore » cross sections and for the integrated contributions of the low-lying strength to the calculated dipole spectra agree very well with the available experimental data.« less