Interplay between Microscopic Diffusion and Local Structure of Liquid Water
We present a quasielastic neutron scattering (QENS) study of single-particle dynamics in pure water, measured at temperatures between 256 and 293 K along an isobaric path at 200 MPa. A thorough analysis of the spectral line shapes reveals a departure from simple models of continuous or jump diffusion, with such an effect becoming stronger at lower temperatures. We show that such a diverging trend of dynamical quantities upon cooling closely resembles the divergent (anomalous) compressibility observed in water by small-angle diffraction. Such an analogy suggests an interesting interplay between single-particle diffusion and structural arrangements in liquid water, both bearing witness of the well-known water anomalies. In particular, a fit of dynamical parameters by a Vogel-Tammann-Fulcher law provides a critical temperature of about 220 K, interestingly close to the hypothesized position of the second critical point of water and to the so-called Widom line.
- Research Organization:
- BROOKHAVEN NATIONAL LABORATORY (BNL)
- Sponsoring Organization:
- DOE - OFFICE OF SCIENCE
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 1020870
- Report Number(s):
- BNL--94688-2011-JA; 39KC02000
- Journal Information:
- Journal of Physical Chemistry B, Journal Name: Journal of Physical Chemistry B Journal Issue: 50 Vol. 114; ISSN 1520-6106
- Country of Publication:
- United States
- Language:
- English
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