Water droplets cooling rapidly by falling in vacuum and are probed by a shot from the x-ray laser before they freeze to ice, providing unique structural information on the deeply supercooled liquid phase in the so-called “no-man’s land”, where water’s mysterious properties become strongly enhanced, but ice is formed so fast that normal measurements cannot be conducted.
Water droplets cooling rapidly by falling in vacuum and are probed by a shot from the x-ray laser before they freeze to ice, providing unique structural information on the deeply supercooled liquid phase in the so-called “no-man’s land”, where water’s mysterious properties become strongly enhanced, but ice is formed so fast that normal measurements cannot be conducted.


Water is the most important liquid for our existence. No life as we know it can survive without water. Water also has many very strange properties, for example that the density of the liquid is higher than ice, the density of water is highest at four degrees and that the compressibility (pressure ability) increases when lowering the temperature. There are a total of 60 different properties where water differs in a remarkable way from most liquids. In addition, these unusual features are greatly enhanced when the water is subcooled.

Despite 100 years of intensive research, there are still many questions that remain unanswered about the water's internal structure and dynamics. An expanded knowledge is of great importance for many areas of Physics, Chemistry, Earth science, Environmental science, Meteorology and Biology.

2.5 million Euros in grants from ERC

Anders Nilsson
Anders Nilsson

Anders Nilsson, Professor of Chemical Physics at Stockholm University, is now awarded around 2.5 million Euros from the European Research Council for the five-year project "Probing the Structure and Dynamics of Water in its Various States".

Scientists use X-rays from both a synchrotron and the unique new X-ray laser sources to investigate the water's internal structure and how that structure is changing in extremely short time intervals, providing information on the dynamics of the individual molecules but also larger aggregates.

“We will create local changes in the electron clouds around water molecules by X-ray radiation absorption. This change and the emission process when a new X-ray photon is emitted, will provide important information about the local environment of the different water molecules”, says Anders Nilsson.

Ultra-short X-ray pulses examines characteristics

X-ray radiation will also be spread against water molecules through an interference process that provides information on the local atomic positions but also if there are more long-distance differences in the structure. Researchers will use the ultra-short X-ray pulses from the X-ray laser sources to investigate the structural and dynamic properties of the water that they sub cool down to temperatures well below freezing. It was recently shown in a cover article in Nature that the short pulse and very rapid cooling allows that water can be investigated before it freezes down to temperature of -45C.

“We will have the opportunity to observe whether water at very low temperatures can actually separate into two different phases of water, which has been proposed in various theories. One of the big questions is whether such a possible phase separation could results in a critical point that leads to large density fluctuations in water under normal circumstances that can explain water's strange properties. We will also explore water surrounded by ions and small organic molecules and water at different interfaces”, says Anders Nilsson.

Research moving from Stanford to Stockholm

After having worked at Stanford University for many years, Anders Nilsson is moving his research to Stockholm University. This has been made possible through a contribution of 125 million SEK for ten years which Stockholm University was granted by the Swedish Research Council in the call to recruit internationally renowned researchers.

In addition to Anders Nilsson, there are 14 researchers in his research group. Today, half of them are at Stanford University and half at Stockholm University. Within 1-2 years Anders Nilsson believes that the entire research team will be in Stockholm.

New activity is being built

“It is fantastic to get the grant. Considering the Research Council's recruitment grants and ERC grant, I can now really plan ahead in peace and quiet. It means we can build up a brand new activity in Stockholm”, says Anders Nilsson.

 The objective is to create a comprehensive understanding of water in a single image based on structure and dynamics at the molecular level.

“Based on this picture, we hope to explain all the remarkable properties of water, from hot state right down to super cold and how the ions and other molecules affect the water structure”.

Funding by the EU Framework Programme

ERC is part of the EU Framework Programme for Research and Innovation, called Horizon 2020. The ERC Advanced Grant is addressed to the already established world-class researchers with significant research efforts over the last ten years. Anders Nilsson's ERC funding is the first ERC grant to the Stockholm University in the Horizon 2020 framework. Another seven ERC Advanced Grants have been awarded to the Stockholm University in the past, within the former EU Framework Programme for Research and Innovation.