Thursday, October 7, 2010

First frictionless [molecular?] superfluid created - New Scientist - New Scientist

First frictionless superfluid created: To see if molecules could be made superfluid, Robert McKellar of the National Research Council of Canada in Ottawa and colleagues turned to hydrogen, which exists as pairs of atoms. The team created a compressed mixture of hydrogen and carbon dioxide gas and shot it through a nozzle at supersonic speeds. Once released, the molecules spread apart, cooling and arranging themselves so that each CO2 molecule sat at the centre of a cluster of up to 20 hydrogens.

To test for superfluidity, the team shone an infrared laser at the clusters at wavelengths that CO2, but not hydrogen, can absorb. This set only the CO2 molecules vibrating. Under normal conditions this movement would be slowed down due to friction between the moving CO2 molecules and the surrounding hydrogen. But the researchers found that for clusters of 12 hydrogen molecules, the hydrogen barely impeded the motion of the CO2

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