CHAPTER 8: Experiments with Large Superfluid Helium Nanodroplets

This chapter aims to look at the properties of large helium nanodroplets from two different perspectives: (i) helium droplets as hosts for assembling and studying clusters at low temperatures; and (ii) helium droplets as systems to be studied on their own. First, the thermodynamics and excitations in large droplets are presented, followed by a primer on the rate of droplet cooling in vacuo. The chapter then proceeds with the description on producing and characterizing the droplets. This is followed by a discussion on the kinetics for different cluster aggregation regimes, such as that for single- and multiple-centre aggregation. Then, experiments involving the spectroscopy of foreign particles and the deposition of metallic clusters for electron microscopy studies are described. Finally, results from recent X-ray coherent diffractive imaging experiments with pure and doped helium nanodroplets are summarized.