论文标题
分子构成和构象对烷烃的正电子结合和an灭的影响
Effect of molecular constitution and conformation on positron binding and annihilation in alkanes
论文作者
论文摘要
作者先前开发的模型势力方法用于研究与分子的正电子相互作用，用于计算$ n $ -Alkanes（C $ _n $ _n $ h $ _ {2n+2} $）的正电子结合能，以及相应的cycloalkanes（C $ _n $ _n $ h $ _ $ _ {2n} $）。对于$ n $ - 烷烃，研究结合能对分子构象的依赖性，其中更紧凑的结构显示出更大的结合能。结果，较大烷烃的热平均结合能（$ n \ gtrsim 9 $）显示在100-600 K的范围内具有强温度依赖性。这表明正电子共振歼灭可以用作旋转（trans-gauche）$ n $ n $ -alkalkanes的旋转（trans-gauche）。特别是，不同构象异构体的存在导致歼灭速率的振动feshbach共振扩大，如用基于陷阱的低能正电子束所观察到的那样。
The model-potential approach previously developed by the authors to study positron interactions with molecules is used to calculate the positron binding energy for $n$-alkanes (C$_n$H$_{2n+2}$) and the corresponding cycloalkanes (C$_n$H$_{2n}$). For $n$-alkanes, the dependence of the binding energy on the conformation of the molecule is investigated, with more compact structures showing greater binding energies. As a result, thermally averaged binding energies for larger alkanes ($n\gtrsim 9$) show a strong temperature dependence in the range of 100-600 K. This suggests that positron resonant annihilation can be used as a probe of rotational (trans-gauche) isomerization of $n$-alkanes. In particular, the presence of different conformers leads to shifts and broadening of vibrational Feshbach resonances in the annihilation rate, as observed with a trap-based low-energy positron beam.
