Researchers prove that water has several liquid states

Water is an ubiquitous liquid with many very unique properties. The way it reacts to changes in pressure and temperature can be completely different from other liquids, and these properties are essential for many practical applications and especially for life as we know it. The causes of these anomalies have long been a source of scientific exploration, but now an international team of researchers that includes Nicolas Giovambattista, professor at CUNY, has proven that water can exist in two different liquid states – a discovery that can explain many anomalous properties of water. Their research appears in an article published in the November 20 issue of the journal Science.

“The possibility that water could exist in two different liquid states was proposed about 30 years ago, based on results obtained from computer simulations,” Giovambattista said. “This counterintuitive hypothesis has been one of the most important questions in the chemistry and physics of water, and a controversial scenario since its inception. This is because experiments that can access both liquid states of the water were very difficult due to the apparently inevitable formation of ice under the conditions where the two liquids should exist. “

The usual “liquid” state of water that we all know is liquid water at normal temperatures (around 25 degrees C). However, the article shows that water at low temperature (about -63 degrees C) exists in two different liquid states, a low-density liquid at low pressure and a high-density liquid at high pressure. These two liquids have significantly different properties and differ by 20% in density. The results imply that, under appropriate conditions, water should exist as two immiscible liquids separated by a thin interface similar to the coexistence of oil and water.

Because water is one of the most important substances on Earth – the solvent of life as we know it – its phase behavior plays a fundamental role in different areas, including biochemistry, climate, cryopreservation, cryobiology, materials science and in many industrial processes where water acts as a solvent, product, reagent, or impurity. It follows that unusual characteristics in the phase behavior of water, such as the presence of two liquid states, can affect many scientific and technical applications.

“It remains an open question how the presence of two liquids can affect the behavior of aqueous solutions in general, and in particular, how the two liquids can affect biomolecules in aqueous environments,” Giovambattista said. “This motivates further studies in the search for potential applications.”

Giovambattista is a member of the doctorate in physics and chemistry. programs at CUNY.

The international team, led by Anders Nilsson, professor of chemical physics at Stockholm University, used complex experiments and computer simulations to prove this theory. The experiments, described as “science fiction type” by Giovambattista, were carried out by colleagues from Stockholm University in Sweden, POSTECH University in Korea, PAL-XFEL in Korea, and the National Accelerator Laboratory. from SLAC graduated in California. Computer simulations were performed by Giovambattista and Peter H. Poole, professor at St. Francis Xavier University at Diplomas Canada. Computer simulations have played an important role in the interpretation of the experiments because these experiments are extremely complex and some observables are not accessible during the experiments.