Nonequilibrium self-assembly of long chains of polar molecules in superfluid helium.

It is shown that in the low-temperature (0.37 kelvin) environment of superfluid helium droplets, long-range dipole-dipole forces acting between two polar molecules can result in the self-assembly of noncovalently bonded linear chains. At this temperature the effective range of these forces is on the nanometer scale, making them important in the growth of nanoscale structures. In particular, the self-assembly of exclusively linear hydrogen cyanide chains is observed, even when the folded structures are energetically favored. This suggests a design strategy for the growth of new nanoscale oligomers composed of monomers with defined dipole (or higher order) moment directions.