Positron binding to hydrocarbon molecules: Calculation using the positron-electron correlation polarization potential
Positron binding to hydrocarbon molecules: Calculation using the positron-electron correlation polarization potential
复制标题
正电子与碳氢化合物分子的结合：使用正电子-电子相关极化电位进行计算
DOI：
10.1140/epjd/e2019-100147-y
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
M. Tachikawa
中科院分区：
文献类型：
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作者：
Y. Sugiura;T. Takayanagi;Y. Kita;M. Tachikawa
摘要萘和烷烃的正电子结合能 (CnH2n+2withn= 3 − 16) 使用相关极化势方法计算，其中短程正电子-电子相关势通过均匀电子气模型的密度泛函表达式进行建模。就萘而言，计算出的正电子结合能与实验测量结果相当一致。在具有线性全反式构象的 CnH2n+2 的情况下，我们发现 n≥ 8 的正电子结合能，而 n≤ 7 的正电子不结合。这个结果不能重现之前的实验研究，其中正电子与 3 ≤ n ≤ 16 的所有烷烃结合。此外，我们计算的 n≥ 9 的正电子结合能远大于实验值，尽管广义梯度近似可以提高计算值。我们还研究了C16H34正电子结合能的构象异构体依赖性，发现正电子结合能显着依赖于构象结构；发夹状和冠状结构通常具有较大的正电子结合能，而单个和多个稀疏结构具有较小的结合能。图解摘要
AbstractPositron binding energies of naphthalene and alkanes (CnH2n+2withn= 3 − 16) are calculated using the correlation polarization potential approach, where the short-range positron–electron correlation potential is modeled by the density-functional expression taken from a homogenous electron gas model. In the case of naphthalene, the calculated positron binding energy is found to reasonably agree with the experimental measurement. In the case of CnH2n+2with the linear all-trans conformation we found positive positron binding energies forn≥ 8 while the positron is not bound forn≤ 7. This result cannot reproduce the previous experimental study, where the positron was bound for all alkanes with 3 ≤n≤ 16. In addition, our calculated positron binding energies forn≥ 9 are much larger than the experimental values although the generalized gradient approximation could improve the calculated values. We also investigated the conformer dependence of the positron binding energy for C16H34and found that the positron binding energies significantly depend on the conformational structure; hairpin-like and crown-like structures generally have large positron binding energies, while single and multiple gauche structures have smaller binding energies.Graphical abstract