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arXiv · 1406.6857

Second critical point of water in supercooled confined water in L,L-diphenylalanine micro/nanotubes

P. M. G. L. Ferreira·S. Kogikoski Jr.·W. A. Alves·H. Martinho
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Abstract

The temperature dependence (10-290 K) of the low-frequency (20-150 cm-1) Raman-active phonon modes of supercooled confined water in L,L-diphenylalanine micro/nanotubes was analysed. The isolated dynamics of a specific geometry of water cluster (pentamer) in supercooled confined regime was studied in detail. A particular mode concerning water-nanotube interaction was also probed. A fragile-to-strong transition at 204 K was observed and related to the crossing of the Widom line. The critical exponent analyses of the relaxation rate data based on mode-coupling theory indicated perfect agreement among experimental data and theory. Our results are consistent with the existence of a second critical point of water.

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P. M. G. L. Ferreira, S. Kogikoski Jr., W. A. Alves, H. Martinho. 2014-06-26. Second critical point of water in supercooled confined water in L,L-diphenylalanine micro/nanotubes. https://doi.org/10.1039/c5cp01055a

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