TURNING ONIONS INTO DIAMONDS. Nano-diamonds can be created without high pressure by squeezing carbon "onions" (nested buckyball-like structures) with ion beams. Graphite material can be made into diamond the hard way, with the use of high pressure (above 10⁶ atmospheres), high temperature, and the use of catalysts. But recently scientists have been able to bombard carbon onions with electron beams and now ion beams as well, and have been able to convert the onions almost completely into diamonds, up to 100 nm in size. Researchers at the Max Planck Institute in Stuttgart (Florian Banhart, banhart@wselix.mpi-stuttgart.mpg.de) use a beam of neon ions to pelt the onions, which act like miniature pressure cells. With larger ion accelerators, one should be able to make macroscopic amounts of irradiation-induced diamond. (Experimental work: Wesolowski et al., Applied Physics Letters, 6 Oct. 1997; theory paper (Zaiser and Banhart) upcoming in Physical Review Letters; figure at Physics News Graphics.)

MOLECULAR HYDROGEN SHOULD BECOME SUPERFLUID if placed on the right surface, say physicists at the University of Illinois (David Ceperley, ceperley@ncsa.uiuc.edu). Superfluids, substances that flow without friction, are few in number: liquid helium-4, special gases of rubidium and sodium atoms (in the form of Bose-Einstein condensates), pairs of helium-3 atoms, and pairs of electrons (which flow through superconductors). The trouble with getting hydrogen molecules (H₂) to become superfluid is that they are all too ready to combine with each other into H₂ solids. By laying them on a silver substrate and by salting them with a pinch of alkali metal atoms, the H₂'s should be able to resist the tendency to solidify all the way down to zero temperature. At 1.2 K they would become a superfluid, the Illinois theorists predict. They believe this can be carried out over the next year, after which experimentalists could explore unique hybrid superfluids, such as H₂/He-4 mixtures. (M.C. Gordillo and D.M. Ceperley, Physical Review Letters, 13 Oct; figure at Physics News Graphics)

A POLYMER THAT CAN TRANSFER ENERGY BETWEEN DIFFERENT LIGHT BEAMS has been demonstrated by researchers at UC-San Diego (W.E. Moerner, 619- 822-0453), opening possibilities for inexpensive and easily manufacturable "optical transistors" that can amplify or attenuate a light beam. The San Diego polymer is an example of a "photorefractive" material, a material that adjusts its structure and electronic properties when two or more light beams combine on it to form an interference pattern. On these materials, light from one beam can bend in such a way as to bounce back in the direction of a second beam, adding energy to it. Inorganic versions of these materials exist, but they are difficult to make and can cost thousands of dollars for a tiny cube. Moerner constructed a polymer whose three main components carried out essential tasks: buckyballs offer electrons, poly (n-vinyl carbazole) (PVK) molecules carry these electrons along their backbone, and PDCST molecules stretch or contract, changing the way light bends in these regions. The researchers demonstrated a "net gain" of about 5, in which one of the laser beams shining on the material gained energy. These materials have numerous possible applications, including correcting distorted images. (Science, 25 July.)