Fusing existing elements to form superheavy ones that don't exist naturally has never been easy. What's more, the signs of possible success are so fleeting and ambiguous that researchers sometimes fool themselves, as happened recently in efforts to forge element 118 (SN: 8/4/01, p. 68: Researchers take an element off the table).
Now, Annette C. Berriman of the Australian National University in Canberra and her colleagues have shown that superheavy atoms are probably even harder to make than scientists thought.
When an ion–a charged atom–plows into a metal foil in a particle accelerator, the projectile's nucleus may strike a target nucleus and stick to it. Two basic outcomes are possible: Either the two nuclei fuse into a lasting larger one, or the emerging heavy nucleus quickly splits, or fissions, into two pieces.