engleski

Universal features in lifetime distribution of clusters in hydrogen bonding liquids

Hydrogen bonding liquids, typically water and alcohols, are known to form labile structures, hence the lifetime of such structures is an important microscopic parameter, which can be calculated in computer simulations. Since these cluster entities are mostly statistical in nature, one would expect that their lifetime would be a broad Gaussian-like function of time, with a single maximum representing the mean lifetime of the cluster structures, both which would weakly dependent on criteria such as the bonding distance and angle. This is indeed the case for the life time of clusters in non-hydrogen bonding simple liquids. Surprisingly, all the hydrogen bonding liquids studied herein display highly hierarchic three types of specific lifetimes The dominant lifetime very strongly depends on the bonding distance criteria and is related to hydrogen bonded pairs. This mode is absent from simple liquids. The secondary and tertiary lifetimes are related to clusters, and are nearly independent on the bonding distance criteria, unlike their distribution. Of these two, only the first one can be linked to the lifetime of simple liquids, which poses the question of why there would be two types of hydrogen bonded clusters. It is the study of different alcohols which allows to answer this question: the first type is related to linear clusters, while the second type would then be related to non-linear clusters. This study reveals that hydrogen bonding liquids have a universal hierarchy of hydrogen bonding lifetimes with a timescale regularity across very different types, such as water and various alcohols, and which depend on the topology of the cluster structures.

Water ; Alcohol ; Hydrogen bond ; Computer simulation

nije evidentirano