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Experimental evidence of fragile-to-strong dynamic crossover in DNA hydration water.

Experimental evidence of fragile-to-strong dynamic crossover in DNA hydration water.

Authors :
Chen, S.-H.
Liu, L.
Chu, X.
Zhang, Y.
Fratini, E.
Baglioni, P.
Faraone, A.
Mamontov, E.
Source :
Journal of Chemical Physics; 11/7/2006, Vol. 125 Issue 17, p171103, 4p, 4 Graphs
Publication Year :
2006

Abstract

We used high-resolution quasielastic neutron scattering spectroscopy to study the single-particle dynamics of water molecules on the surface of hydrated DNA samples. Both H<subscript>2</subscript>O and D<subscript>2</subscript>O hydrated samples were measured. The contribution of scattering from DNA is subtracted out by taking the difference of the signals between the two samples. The measurement was made at a series of temperatures from 270 down to 185 K. The relaxing-cage model was used to analyze the quasielastic spectra. This allowed us to extract a Q-independent average translational relaxation time ≤τ<subscript>T</subscript>> of water molecules as a function of temperature. We observe clear evidence of a fragile-to-strong dynamic crossover (FSC) at T<subscript>L</subscript>=222±2 K by plotting log≤τ<subscript>T</subscript>> versus T. The coincidence of the dynamic transition temperature T<subscript>c</subscript> of DNA, signaling the onset of anharmonic molecular motion, and the FSC temperature T<subscript>L</subscript> of the hydration water suggests that the change of mobility of the hydration water molecules across T<subscript>L</subscript> drives the dynamic transition in DNA. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219606
Volume :
125
Issue :
17
Database :
Complementary Index
Journal :
Journal of Chemical Physics
Publication Type :
Academic Journal
Accession number :
23064385
Full Text :
https://doi.org/10.1063/1.2372491