Scientists search for the elusive super-element
Earlier this fall, Peter Armbruster and Gottfried Muncenberg reported their research team in Darmstadt, West Germany, had created the heaviest chemical element known - Element 109. Now, in collaboration with a California research team, they are after a more glittering prize - Element 114.
If it can indeed be created, this will show skeptics that the pursuit of the super-elements - elements far heavier than any so far identified - is not a modern analogue of the legendary (and futile) search for the Holy Grail.
Theory suggests that such elements would be highly unstable. Yet some physicists believe that Element 114 could represent an exception. It could mark an ''island of stability'' in a sea of instability, to use physicists' jargon. The successful creation of Element 109 has buoyed the hopes of those who think this may be so.
Chemists and physicists are fascinated with the super-elements, even though these have no currently defined practical use. If they can indeed be created, this will confirm theory and give new insight into the nature of the atomic nucleus. That knowledge could well have practical uses, although these may not be obvious now.
The nucleus of an element consists of two kinds of major particles - protons, which have a positive electric charge, and neutrons, which have no electric charge. Elements are classified by atomic number, which is essentially the number of protons they carry. Their weight, however, is determined by the total number of particles. The heavier they are, the more unstable that collection of protons and neutrons is likely to be.
Two years ago, when Element 106 was the heaviest known, many physicists wondered if anything heavier could be put together. Then last year, the Darmstadt researchers reported creation of Element 107. A Soviet team at the Dubna research center made a similar announcement in 1976, but that claim has not been substantiated.
By bombarding bismuth (83 protons and 126 neutrons) with iron (26 protons and 32 neutrons), the Darmstadt researchers managed to create Element 109 last Aug. 29. It is a tricky experiment. If projectile and target come together too fast, everything just breaks apart. If they collide too slowly, they cannot overcome the electrical repulsion between them. But if they meet gently, they may fuse together. In 10 days of work and after many trillions of collisions, one atom of 109 finally formed and lasted the few milliseconds needed to identify it.
This has encouraged Al Ghiorso of the Lawrence Berkeley Laboratory in California, who is leading the collaborative work with Darmstadt. He says he now gives the current search for Element 114 ''one chance in a hundred'' of success, whereas ''before 107 and 109, I used to think it was only one chance in a million.''
If research scientists do create Element 114, this will only encourage them to try for even heavier nuclear combinations. Unless and until there is definite proof that it is futile, this search will likely continue.