POSITRONIUM DECAY IN MOLECULAR SUBSTANCES
POSITRONIUM DECAY IN MOLECULAR SUBSTANCES
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DOI：
10.1103/physrev.120.1289
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发表时间：
1960-01-01
期刊：
影响因子：
--
通讯作者：
WALKER, WW
中科院分区：
文献类型：
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作者：
BRANDT, W;BERKO, S;WALKER, WW
致密分子物质中电子偶素（Ps）波函数的正电子分量与晶格波函数的重叠决定了正电子偶素中正电子的2 γ湮灭率（通过从晶格拾取电子（τ 2衰变）），以及部分2 γ角关联。Ps作为一个探针的依赖性的单粒子波函数在晶格结构的晶格参数，原子晶格参数和自由基分子相互作用。为了探索这种探测的灵敏度，在Wigner-Seitz近似下计算了不同晶格结构的Ps波函数，并导出了τ 2衰变对晶格参数的依赖关系。通过对不同物理状态下仔细表征的分子物质进行τ 2测量，实验测试了这种依赖性。它被证实，温度和状态的依赖性主要是一个“自由体积”的意义上说，Ps和晶格波函数之间的重叠随着晶格间距的增加而减少的效果。的自湮灭率和稳定性的Ps上的球形限制的影响被证明是小的半径相关的分子晶格。
The overlap of the positron component of the wave function of positronium (Ps) in dense molecular substances with the lattice wave function determines the 2 γ annihilation rate of positrons bound in orthopositronium via electron pickup from the lattice (τ 2 decay), and in part the 2 γ angular correlation. Ps acts as a probe for the dependence of one-particle wave functions in lattices on structural lattice parameters, and of radical-molecule interactions on atomic lattice parameters. To explore the sensitivity of this probe Ps wave functions are calculated for different lattice structures in the Wigner-Seitz approximation, and the dependence of τ 2 decay on lattice parameters is derived. This dependence was tested experimentally by τ 2 measurements on carefully characterized molecular substances in different physical states. It is confirmed that the temperature and state dependence is primarily a" free volume" effect in the sense that the overlap between the Ps and lattice wave functions decreases with increasing lattice spacing. The effects of a spherical confinement on the self-annihilation rates and stability of Ps are shown to be small for radii relevant to molecular lattices.