液态甲烷中的正电子素气泡态和化学动力学

液态甲烷中的正电子素气泡态和化学动力学 POSITRONIUM BUBBLE STATES AND CHEMICAL DYNAMICS IN LIQUID METHANE 王少阶 Wang Shaojie~ 1 2 first-author H.Nakanishi 1 2 简杨青 1 2 武汉大学物理系 武汉大学物理系 . J. Wang), H. Nakanishi,~ . J. Wang), H. Nakanishi,~ 美国密苏里大学堪萨斯城分校 美国密苏里大学堪萨斯城分校 测量了92—150K温度范围内具有饱和蒸气压的高纯液态甲烷中正电子寿命谱随温度的变化。实验测得的正电子素形成率约36%,且正—正电子素（o-P ） 的寿命长达5～7ns。计算了液态甲烷中的气泡尺寸及微观表面张力随温度的变化。此外还研究了氧杂质与o-P 的 化学反应动力学,测得反应率常数K P 与温度的关系及其转折点温变T o ≈100K。还求得T < T o 时和T > T o 时的化学反应激活能分别为E α =3.70kJ/mol和E α ′ =-8.68kJ/mol。 Positron lifetime measurements have been performed on the high purity liquid methane with saturated vapor pressure in temperature range from 92K to 150K. The positron lifetime spectra were resolved into three components which are attributed to p-Ps, free positrons and o-Ps annihilation. The Ps bubble model was supported by the long o-Ps lifetime （5-7ns） and high Ps formation probability （36%）. The bubble size and surface tension were estimated from bubble model and experimental o-Ps lifetime. On other hand, Ps chemical reaction with oxygen impurity in liquid methane was studied. The Ps chemical reaction rate K PS , turnover temperature （T 0 =100K）, the anormal" and "negative" activation energies E α =3.70kJ/mol and E α =-8.68kJ/mol were obtained respectively. 正电了素 芷电子湮没 化学动力学 positronium positron annihilation chemical dynamics 1991-03-01 2021-04-01 3