title: Slow processes in supercooled o-terphenyl: relaxation and decoupling.
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 β 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 β process from the α process and, due to the difference of the length scales between the α and the slow β 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 β process could be obtained as an anomalous momentum transfer (q) dependence of <τ>(<τ> ∝q(-2.9)) at 265 K, observed at q values of 18-48  nm(-1).
authors.affiliation: Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494, Japan.
authors.forename: Makina
authors.initials: M
authors.lastname: Saito
authors.forename: Shinji
authors.initials: S
authors.lastname: Kitao
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kurokuzu
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Yoda
authors.forename: Makoto
authors.initials: M
authors.lastname: Seto