Catalysis of impurities coalescence by quantized vortices in superfluid helium with nanofilament formation

A dramatic effect of quantized vortices in superfluid helium on the rate of coalescence of suspended impurities has been predicted; such a catalytic process should result in the formation of fiber-like structures having primarily nanothickness. That should be valid for any impurity and it may be used as a basis for a universal method of producing nanowires and nanotubes. Experiments on the imbedding of molecular hydrogen into liquid helium have supported these conclusions. They showed that: (i) in normal liquid He the coalescence led to the formation of spherical microparticles carried by turbulent motion of the liquid; (ii) in the superfluid only very long filaments were observed, which behaved as quantized vortices should do. These filaments are fiber-like hydrogen crystals and survive the transition of the liquid helium to the normal state. The promises for using this phenomenon in basic and applied sciences are outlined. (C) 2009 American Institute of Physics. [DOI:10.1063/1.3081156]