Lackner Florian, Ernst Wolfgang E
Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria, European Union.
J Phys Chem Lett. 2018 Jul 5;9(13):3561-3566. doi: 10.1021/acs.jpclett.8b01530. Epub 2018 Jun 14.
Besides the use as cold matrix for spectroscopic studies, superfluid helium droplets have served as a cold environment for the synthesis of molecules and clusters. Since vibrational frequencies of molecules in helium droplets exhibit almost no shift compared to the free molecule values, one could assume the solvated particles move frictionless and undergo a reaction as soon as their paths cross. There have been a few unexplained observations that seemed to indicate cases of two species on one droplet not forming bonds but remaining isolated. In this work, we performed a systematic study of helium droplets doped with one rubidium and one strontium atom showing that besides a reaction to RbSr, there is a probability of finding separated Rb and Sr atoms on one droplet that only react after electronic excitation. Our results further indicate that ground-state Sr atoms can reside at the surface as well as inside the droplet.
除了用作光谱研究的冷基质外，超流氦滴还作为分子和团簇合成的冷环境。由于与自由分子值相比，氦滴中分子的振动频率几乎没有偏移，因此可以假设溶剂化粒子无摩擦移动，并且一旦它们的路径交叉就会发生反应。有一些无法解释的观察结果似乎表明，一个液滴上的两种物质没有形成键而是保持分离。在这项工作中，我们对掺杂有一个铷原子和一个锶原子的氦滴进行了系统研究，结果表明，除了反应生成RbSr外，在一个液滴上还可能发现分离的Rb和Sr原子，它们只有在电子激发后才会反应。我们的结果进一步表明，基态Sr原子可以存在于液滴表面以及液滴内部。
