Abstract
A quasielastic neutron-scattering experiment carried out on a backscattering spectrometer with sub- μeV resolution in the temperature range of 200-250 K has revealed the dynamics of surface water in cerium oxide on the time scale of hundreds of picoseconds. This slow dynamics is attributed to the translational mobility of the water molecules in contact with the surface hydroxyl groups. The relaxation function of this slow motion can be described by a slightly stretched exponential with the stretch factor exceeding 0.9, which indicates almost a Debye-type dynamics. Down to about 220 K, the temperature dependence of the residence time for water molecules follows a Vogel-Fulcher-Tamman law with the glass transition temperature of 181 K. At lower temperatures, the residence time behavior abruptly changes, indicating a fragile-to-strong liquid transition in surface water at about 215 K.
| Original language | English |
|---|---|
| Article number | 171101 |
| Journal | Journal of Chemical Physics |
| Volume | 123 |
| Issue number | 17 |
| DOIs | |
| State | Published - Nov 1 2005 |
| Externally published | Yes |
Funding
The author is indebted to Professor S.-H. Chen for a valuable discussion, and to W. Kamitakahara and V. Garcia Sakai for critical reading of the manuscript. Utilization of the DAVE package for the data analysis is acknowledged. This work utilized facilities supported in part by the National Science Foundation under Agreement No. DMR-0086210.
| Funders | Funder number |
|---|---|
| National Science Foundation | DMR-0086210 |