Ultrafast laser used to study deep molecular activity of water

AMSTERDAM, Netherlands, Sept. 19 (UPI) -- Water in its liquid form is far more complex a substance than previously thought thanks to research conducted using an incredibly quick laser capable of capturing the activity of molecular bonds in sub-fractions of a second.

A team of researchers from the Max Planck Institute for Polymer Research (MPI-P) in Germany and the Netherlands' FOM Institute AMOLF have been able to distinguish just how quickly water molecules can alter their bonds to other molecules. Such observations were previously impossible to observe due to the actions' swiftness, which is thought to take as little as a femtosecond -- or one quadrillionth of a second.

In a study published in the journal Nature Communications, researchers discuss their method of retrieving information regarding water's expansive heterogeneity. The liquid's hydrogen bond network causes notable intermolecular interactions within itself which can only be observed using sub-picosecond infrared lasers.

The laser pulses, or ultrafast laser spectroscopy, helped researchers find the vibrations of oxygen-hydrogen bonds in water last longer (up to 1 picosecond) for water molecules with significant separation between each other. Those close together experience vibrations close to .2 picoseconds long. "In other words, the weakly bound water molecules remain weakly bound for a remarkably long time," a statement released by MPI-P said.

The lifetime of local water structures is probed using ultra fast laser pulses. Photo by Yuki Nagata/MPI-P

Liquid water is arguably the most unique molecular liquid on the planet -- or possibly in the universe -- due to its expert resistance to temperature changes and thus moderating the earth's climate. Its dynamic allows it to form structures, maintain high surface tension resist dramatic pH alterations.

"Seventy-one percent of the earth's surface is covered with water," says MPI-P director Mischa Bonn. "As most chemical and biological reactions on earth occur in water or at the air water interface in oceans or in clouds, the details of how wter behaves at the molecular level are crucial. Our results show that water cannot be treated as a continuum, but that specific local structures exist and are likely very important."