- Published on Thursday, 18 May 2017 15:20
The importance of nuclear quantum effects is well known for in solid systems at very low temperatures (T<10K). At higher temperature (above ~20-50K) usually the contribution of these quantum effects to structural relaxation is considered minor. Traditionally, researchers who study the structural relaxation in liquids and the glass transition neglect to consider quantum effects. However, it is becoming increasingly evident when studying light molecules (such as water) at temperature of 100-200K that quantum effects might play an important role in structural dynamics, and provide non-negligible contributions at temperatures as high as ambient.
In this EPJ E Colloquium paper, Novikov and Sokolov discuss experimental evidence of quantum effects in the glass transition of liquids comprising light molecules and propose theoretical descriptions to explain these effects. They show that quantum effects may qualitatively change the temperature-dependent behaviour of the structural relaxation time in super-cooled liquids, leading to deviations of some properties of the glass transition that are well-established at low temperatures. They argue that the unusual dynamical behaviour of water at low temperatures, including apparent fragile-to-strong crossover, can be ascribed to nuclear quantum effects.
V.N. Novikov and A.P. Sokolov (2017),
Quantum effects in dynamics of water and other liquids of light molecules,
European Physical Journal E, DOI 10.1140/epje/i2017-11546-0