Cluster Aggregation in Bosonic and Fermionic Helium Nanodroplets
ORAL
Abstract
Bosonic superfluid helium-4 droplets obtained in molecular beams have sizable angular momentum, which manifests itself physically in the form of quantized vortices. In our previous works, vortices have been visualized via ultrafast X-ray coherent diffractive imaging using xenon as a contrast agent. Xenon atoms are attracted to the vortex cores leading to the formation of filament – shaped clusters [1]. Here, we study the formation of clusters in non-superfluid fermionic helium-3 droplets, which also rotate but are devoid of any quantum vortices. It was found that in distinction to helium-4, xenon atoms inside helium-3 form loose aggregates arranged into rings on the periphery of the droplets. This is because in normal fluid helium-3 droplets, dopants are fixed in the rotating frame. Thus, heavy xenon atoms are pushed to the droplets’ periphery by centrifugal forces where they recombine into ring-shaped structures.
*This material is based upon work supported by the National Science Foundation under Grant No. DMR-1701077 (A.F.V.). Use of the Linac Coherent Light Source (LCLS), SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515.
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Presenters
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Alexandra J Feinberg
- Univ of Southern California