Three-Dimensional Shapes of Spinning Helium Nanodroplets
Abstract
A significant fraction of superfluid helium nanodroplets produced in a free-jet expansion have been observed to gain high angular momentum resulting in large centrifugal deformation. We measured single-shot diffraction patterns of individual rotating helium nanodroplets up to large scattering angles using intense extreme ultraviolet light pulses from the FERMI free-electron laser. Distinct asymmetric features in the wide-angle diffraction patterns enable the unique and systematic identification of the three-dimensional droplet shapes. The analysis of a large dataset allows us to follow the evolution from axisymmetric oblate to triaxial prolate and two-lobed droplets. We find that the shapes of spinning superfluid helium droplets exhibit the same stages as classical rotating droplets while the previously reported metastable, oblate shapes of quantum droplets are not observed. Our three-dimensional analysis represents a valuable landmark for clarifying the interrelation between morphology and superfluidity on the nanometer scale.
Keywords
Cite
@article{arxiv.1802.10584,
title = {Three-Dimensional Shapes of Spinning Helium Nanodroplets},
author = {Bruno Langbehn and Katharina Sander and Yevheniy Ovcharenko and Christian Peltz and Andrew Clark and Marcello Coreno and Riccardo Cucini and Marcel Drabbels and Paola Finetti and Michele Di Fraia and Luca Giannessi and Cesare Grazioli and Denys Iablonskyi and Aaron C. LaForge and Toshiyuki Nishiyama and Verónica Oliver Álvarez de Lara and Paolo Piseri and Oksana Plekan and Kiyoshi Ueda and Julian Zimmermann and Kevin C. Prince and Frank Stienkemeier and Carlo Callegari and Thomas Fennel and Daniela Rupp and Thomas Möller},
journal= {arXiv preprint arXiv:1802.10584},
year = {2019}
}