Positronium scattering from closed-shell atoms and ions
Positronium scattering from closed-shell atoms and ions
复制标题
闭壳原子和离子的正电子散射
DOI：
10.1103/physreva.65.012509
复制
发表时间：
2001
影响因子：
2.9
通讯作者：
I. Ivanov
中科院分区：
文献类型：
--
作者：
J. Mitroy;I. Ivanov
用固定核随机变分方法研究了He、Ne、Ar、Li+、Na+和K+对正对电子离子的散射。Ps-He散射长度为1.57a(0)，与三个正电子寿命实验的阈值截面一致。Ps-Ne和Ps-Ar体系的散射长度分别为1.55a(0)和1.79a(0)。散射长度之间只有15%的变化，这与Coleman等人的实验是一致的。理论物理。B 27,981(1994)]，他发现He， Ne和Ar的低能截面大小大致相同。Li+、Na+和K+对Ps的散射长度分别为12.9a(0)、28.5a(0)和-1.9a(0)。Ps-K+散射长度相对较小的幅度有力地支持了先前关于Ps-K+体系不支持束缚态的建议。湮灭参数(1)Z（eff）也作为分析的一部分进行了计算。由于在计算湮灭矩阵元素时没有考虑电子-正电子的短程相关关系，(1)Z（eff）的现值比公认的实验值约小2.5-3倍。
The scattering of orthopositronium from He, Ne, Ar, Li+, Na+, and K+ is investigated with the fixed-core stochastic variational method. The scattering length for Ps-He scattering was 1.57a(0), a value consistent with the threshold cross sections derived from three positron lifetime experiments. The scattering lengths for the Ps-Ne and Ps-Ar systems were 1.55a(0) and 1.79a(0), respectively. That there was only a 15% variation among the scattering lengths is compatible with the experiment of Coleman et al. [J. Phys. B 27, 981 (1994)], who found the low-energy cross sections for He, Ne, and Ar to be about the same size. The scattering lengths for Ps scattering from Li+, Na+, and K+ were 12.9a(0), 28.5a(0), and -1.9a(0). The relatively small magnitude of the Ps-K+ scattering length strongly supports previous suggestions that the Ps-K+ system does not support a bound state. The annihilation parameter (1)Z(eff) has also been computed as part of the analysis. The present values of (1)Z(eff) are about 2.5-3 times smaller than the accepted experimental values since short-range electron-positron correlations were not taken into consideration when the annihilation matrix element was evaluated.