Fragile-to-Strong Crossover in Supercooled Liquids Remains Elusive

TL;DR

This paper critiques a previous claim of a fragile-to-strong crossover in supercooled liquids, clarifying that the observed data follows a consistent parabolic trend without a crossover, and addressing misinterpretations in earlier work.

Contribution

It clarifies the distinction between onset crossover and fragile-strong crossover and demonstrates that supercooled liquid data does not exhibit a crossover to another functional form.

Findings

Supercooled liquid transport data follows a parabolic function.

No evidence of a fragile-to-strong crossover in the data.

Previous claims misinterpreted anomalous data as a crossover.

Abstract

A critique of a recent paper [Mallamace et al PNAS 2010 107 (52) 22457-2246] purporting the existence of a fragile-to-strong crossover in super cooled liquids is presented. It is shown that Mallamace et al have mistaken the onset crossover with the fragile-strong crossover. Moreover, it is shown that supercooled liquid transport data follows the expected parabolic function, without a crossover to another functional form, and that Mallamace et al have obscured this fact by singling out anomalous data as examples.