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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.
- 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