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物理学报. 1990, 39(7): 106-111.
doi: 10.7498/aps.39.106.
用正电子湮没寿命谱研究凝聚态甲烷的温度关系
- 收稿日期: 1988-03-09
- 刊出日期: 2005-06-17
摘要: 在30—150K温度范围内,测量了高纯凝聚态甲烷中的正电子寿命谱随温度的变化。在固态甲烷中,正电子素(简称Ps)在自由体积中形成,形成率为27%。正-正电子素(其符号为o-Ps)的寿命随温度变化的特征可用o-Ps在热激活空位型缺陷中的捕获来说明,且由Ps捕获模型和实验测得的o-Ps寿命求得缺陷激活能Ea=0.10±0.02eV。在液态甲烷中,Ps形成率高达36%,且o-Ps寿命长达5—7ns,这表明液态甲烷中形成了Ps气泡态。我们用经验公式估算了这种气泡的尺寸及其微观表面张力。
English Abstract
TEMPERATURE DEPENDENCE OF CONDENSED METHANE STUDIED BY POSITRON LIFETIME MEASUREMENTS
- Received Date:
09 March 1988
- Published Online:
17 June 2005
Abstract: Positron lifetime spectra have been measured as a function of temperature from 30 K to 150 K in condensed methane. In solid phase, the positronium (Ps) formation in free volume and the Ps yield of 27% were observed. The sigmoidal variation of o-Ps lifetime with temperature was interpreted by Ps trapping in the thermally activated defects. The activated energy Ea = 0.10±0.02 eV was derived in terms of Ps trapping model. In liquid methane with saturated vapor pressure, the results that o-Ps lifetime is 5-7ns and Ps formation probability is 36% indicate the Ps bubble formation. The temperature dependence of the bubble size and surface tension were estimated.
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