Goulart Marcelo, Kuhn Martin, Rasul Bilal, Postler Johannes, Gatchell Michael, Zettergren Henning, Scheier Paul, Echt Olof
Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
Phys Chem Chem Phys. 2017 Oct 25;19(41):27968-27973. doi: 10.1039/c7cp04999d.
Mass spectra of helium nanodroplets doped with H and coronene feature anomalies in the ion abundance that reveal anomalies in the energetics of adsorption sites. The coronene monomer ion strongly adsorbs up to n = 38 H molecules indicating a commensurate solvation shell that preserves the D symmetry of the substrate. No such feature is seen in the abundance of the coronene dimer through tetramer complexed with H; this observation rules out a vertical columnar structure. Instead we see evidence for a columnar structure in which adjacent coronenes are displaced in parallel, forming terraces that offer additional strong adsorption sites. The experimental value for the number of adsorption sites per terrace, approximately six, barely depends on the number of coronene molecules. The displacement estimated from this number exceeds the value reported in several theoretical studies of the bare, neutral coronene dimer.
掺杂有H和并五苯的氦纳米滴的质谱在离子丰度上呈现出异常，这揭示了吸附位点能量学方面的异常。并五苯单体离子强烈吸附多达n = 38个H分子，表明存在一个保持底物D对称性的相称溶剂化壳。在与H络合的并五苯二聚体至四聚体的丰度中未观察到此类特征；这一观察结果排除了垂直柱状结构。相反，我们看到了一种柱状结构的证据，其中相邻的并五苯平行位移，形成了提供额外强吸附位点的平台。每个平台的吸附位点数的实验值约为六个，几乎不依赖于并五苯分子的数量。根据这个数量估计的位移超过了几项关于裸的、中性并五苯二聚体的理论研究报告的值。
