A research team from the Joint Institute for Nuclear Research (Dubna, Russia), and DOE's Lawrence Livermore National Laboratory (LLNL; Livermore, CA), announced that they have discovered element 114. Because the atom lasted 30 sec before breaking into lighter elements, the researchers believe element 114 represents an "island of stability" with a long-lived, superheavy nuclei. The discovery has not yet undergone official peer review.
Discovery And Verification
Island Of Stability
Discovery And Verification (Back to Top)
To create a single atom of element 114, researchers worked for 40 days. During the experiment, Russian scientists bombarded a film of plutonium-244, supplied by LLNL, with a beam of calcium-48 atoms, says Dubna's Yuri Oganessian. Work was completed at the end of December 1998.
The atom was detected because it disintegrated into lighter and lighter elements, from atomic number 112 to 110 to 108 and so on. Kent Moody of LLNL says his team's recently completed data analysis identifies the atom as element 114 "to greater than a 99% probability."
Isotopes provided another clue to the atom's identity. Several newly discovered isotopes in the decay chain had exceptionally long life spans. For example, isotopes of elements 112 and 108 in the decay chain lasted 15 minutes and 17 minutes, respectively, before disintegrating. These are not foolproof verification tools, however, as it is difficult to identify novel decay products.
Further experiments should help to settle doubts regarding the atom's identity. Although the discovery has not yet undergone peer review for publication, it has been well received by researchers in the heavy-element field.
Island Of Stability (Back to Top)
After its creation in the laboratory in Dubna, element 114 lasted 100,000 times longer than element 112the last new element to be discovered. Many believe that this stability is more important than the discovery of the element itself.
For 30 years, theorists have predicted that an island of stability would exist for extremely heavy elements. In this island, exotic elements would have long lifespans that allow researchers to conduct exhaustive studies of their nuclear behavior and chemistry.
Traditionally, experiments have shown that nuclei decay faster as they become heavier. This is because the increased number of positively charged protons repel each other, shattering the nucleus. Element 114 may not have suffered the same fate because its uncharged neutrons may have arranged themselves among the protons, making the nuclei more durable than would otherwise be expected.
A report of the discovery appeared Jan. 19, 1999, on Science's online news service.
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