POSITRONIUM IN ALKALI-HALIDES
POSITRONIUM IN ALKALI-HALIDES
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DOI：
10.1143/jpsj.57.329
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发表时间：
1988-01-01
影响因子：
1.7
通讯作者：
FUJIWARA, K
中科院分区：
文献类型：
--
作者：
KASAI, J;HYODO, T;FUJIWARA, K
用高分辨率一维角相关仪测量了几种碱卤化物晶体湮灭γ射线的动量分布。在NaBr和RbCl中形成bloch型正电子离子（Ps）是最近才被证实的，而在liff、KF和CsI中没有发现它的证据。通过分析Ps动量分布的低温行为，确定了Ps在布洛赫态的有效质量。在所研究的碱卤化物中，有效质量均大于真空中自由Ps质量。详细分析了Ps动量分布对KI和KBr的温度依赖性。在这些材料中也观察到先前报道的NaF和KCl的温度诱导转变为自捕获态。
Momentum distribution of annihilation γ rays from several alkali halide crystals has been measured using high resolution 1D angular correlation apparatuses. Formation of Bloch-type positronium (Ps) in NaBr and RbCl has been newly confirmed, while no evidence for it has been seen in LiF, KF, and CsI. Effective mass of the Ps in the Bloch state has been determined by analyzing the low temperature behavior of the Ps momentum distribution. The effective mass is larger than the free Ps mass in vacuum in all the alkali halides investigated. Detailed analysis of the temperature dependence of the Ps momentum distribution has been made on KI and KBr. Temperature induced transition to the self-trapped state as previously reported in NaF and KCl has been observed also in these materials.