A new state of matter was discovered when researchers put water molecules under extreme confinement.
Scientists from the Oak Ridge National Laboratory in Tennessee have squeezed water molecules between hexagonal beryl crystals and discovered that the water acts in a completely new way. The water molecules start moving according to the laws of quantum mechanics, exhibiting a phenomenon called quantum tunneling.
Quantum tunneling allows particles to move through energy barriers. If you have a quantum particle in a box, it might be able to pass through the wall of the box even if it doesn’t have the energy to jump out of the box. In this specific case, the water molecules in the beryl crystal are no longer in a specific position, but instead are spread out.
“This discovery represents a new fundamental understanding of the behavior of water and the way water utilizes energy,” Lawrence Anovitz, co-author of the study, said in a statement. “It’s also interesting to think that those water molecules in your aquamarine or emerald ring – blue and green varieties of beryl – are undergoing the same quantum tunneling we’ve seen in our experiments.”
The beryl hexagonal channel is only 0.1 billionths of a meter across (a typical atom is about five times smaller), so once water is injected, it really feels the squeeze. Using simulations, the team predicted that the water molecules would organize themselves in a ring shape.
They verified this using neutron scattering, a common technique employed in the investigation of materials. They worked out that their average energy at almost absolute zero was about 30 percent less than it is in ice.
“This is in complete disagreement with accepted models based on the energies of its vibrational modes,” said Alexander Kolesnikov, lead author of the study.
This research, published in Physical Reviews Letters, has applications beyond this limited case. Water is thought to exhibit a similar behavior in important geological, chemical, and biological processes. Understanding this new and curious state of matter can help scientists to better model how water moves through carbon nanotubes, mineral interfaces, and through cell membranes.