Slow processes in supercooled o-terphenyl: relaxation and decoupling.
Phys Rev Lett
; 109(11): 115705, 2012 Sep 14.
Article
in En
| MEDLINE
| ID: mdl-23005649
ABSTRACT
We mapped the relaxation times of inter- and intramolecular correlations in o-terphenyl by a quasielastic scattering method using nuclear resonant scattering of synchrotron radiation. From the obtained map, we found that the slow ß process is decoupled from the α process at 278 K, and this temperature is clearly below the previous decoupling temperature of 290 K, at which the α-relaxation dynamics changes. Then, it was also concluded that sufficient solidlike condition achieved by further cooling from 290 K is required to decouple the slow ß process from the α process and, due to the difference of the length scales between the α and the slow ß processes, these two averaged relaxation times <τ> are concluded not to cross as an extrapolation assumed so far. Furthermore, evidence of the restricted dynamics of the slow ß process could be obtained as an anomalous momentum transfer (q) dependence of <τ>(<τ> âq(-2.9)) at 265 K, observed at q values of 18-48 nm(-1).
Search on Google
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Phys Rev Lett
Year:
2012
Type:
Article
Affiliation country:
Japan