Thanks to a reader for sending me a link to this article from Physics World which reports how a team of researchers at the US Army Research Laboratory have observed nuclear excitation by electron capture (NEEC) – where an atomic nucleus becomes excited when it absorbs an electron.
From the Article:
To make their observations, the team produced atoms of the radioactive isotope molybdenum-93 and had them absorb electrons of energy that they believed would cause NEEC. They predicted that if the nucleus did become excited, its sequence of decay products would be different to that of an unexcited nucleus. Determining the decay sequence involved analysing gamma-ray emissions from decay products with differing half-lives. As hoped, their measurements matched up with the theoretical predictions of the unique decay sequence of an excited molybdenum-93 nucleus.
One important consequence of the discovery is that it provides a possible explanation for the abundance of elements such as gold and platinum in the universe. If NEEC were a fairly common process in nature, then certain elements could transform into others after being created in stars. The team’s work could also lead to the development of new technologies that harness the energy of excited nuclei. This, according to Carroll, could lead to power sources with an energy density 100,000 times greater than that in chemical batteries.
The full research report has been published in Nature here.