Ion Bombardment of Metals (image) Brown University Caption This shows a computer-model image of an island of metal atoms formed after bombardment by noble gas ions. Atoms disturbed by the bombardment cluster together under the surface and then glide back up in a matter of 2.1 trillionths of a second, or picoseconds . Credit Kim Lab/Brown University Usage Restrictions Credit required Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.