Researchers at the SLAC National Accelerator Laboratory have managed to produce an extreme physical object – a molecule that attracts more electrons than it can keep until it explodes. This object, dubbed a molecular black hole, caught researchers by surprise as they weren’t expecting something quite so intense.
As reported in Nature, scientists used the world’s most powerful X-ray laser to remove almost all the electrons from the largest atom in a molecule, from the inside out. Within 30 femtoseconds (millionths of a billionth of a second), more than 50 electrons from the rest of the molecule came rushing in, which quickly led to the explosive demise of the molecule.
While scientists have seen similar behavior before when this experiment was attempted with less intense beams or isolated atoms, they've not seen it to this magnitude. The molecular black hole is not just really cool as a new discovery, but it provides clues on how X-ray lasers affect molecules. This is important because we use X-ray lasers to study how individual biological systems work.
"For any type of experiment you do that focuses intense X-rays on a sample, you want to understand how it reacts to the X-rays," experiment leader Daniel Rolles, of Kansas State University, said in a statement. "This paper shows that we can understand and model the radiation damage in small molecules, so now we can predict what damage we will get in other systems."
The researchers looked at three samples: Individual xenon atoms, each with 54 electrons, and two molecules containing a single iodine atom, which has 53 electrons. By using the powerful laser, they started kicking electrons out of the atoms. In the xenon, the atom was left with only the most strongly bound electrons, but the iodine behaved differently.
In the molecule, the iodine began attracting electrons from the hydrogen and carbon atoms as well. Iodine was expected to lose 47 electrons, but the iodine in the smaller molecule lost 54 electrons.
"We think the effect was even more important in the larger molecule than in the smaller one, but we don't know how to quantify it yet," lead author Artem Rudenko added. "We estimate that more than 60 electrons were kicked out, but we don't actually know where it stopped because we could not detect all the fragments that flew off as the molecule fell apart to see how many electrons were missing. This is one of the open questions we need to study."
The power of the laser has allowed the study of reactions like photosynthesis in never-seen-before detail, and it remains an incredibly powerful instrument. The X-ray pulses are 100 times more intense than if you concentrate all the sunlight we receive on Earth onto a single thumbnail.