Magnetic deflection of doped helium nanodroplets as a probe of spin relaxation

Beams of superfluid helium nanodroplets have found many uses as an inert cryogenic environment in which to study species of interest, but the way in which dopant spin states thermalize within the nanodroplets remains uncertain. Stern-Gerlach deflection of such a beam by an inhomogeneous magnetic field can provide information about the spin polarization of magnetic atoms and molecules within the helium matrix. In our lab, such experiments have been performed on: monatomic bismuth and europium; a selection of chloride salts; and the sodium dimer molecule (which stays along the surface of the droplet rather than sinking to the center like the rest). Preliminary results indicate a significant difference in spin relaxation times between atoms and molecules, with the latter fully thermalizing within the time spent in the field while the former are only partially relaxed.