Abstract
The translational diffusion of rubrene in the fragile molecular glass former, sucrose benzoate (SB) (fragility index m≈94), has been studied from T g+6 K to T g+71 K(T g=337 K) by using the technique of holographic fluorescence recovery after photobleaching. In the temperature range of the measurements, the translational relaxation functions were observed to decay exponentially, indicating that Fick's law of diffusion governs the translational motion of rubrene in sucrose benzoate. The value of the translational diffusion coefficient D T obtained from the 1/e time of the translational relaxation function varied from 5.3×10 -15 cm 2 s -1 at 343 K to 5.0×10 -9 cm 2 s -1 at 408 K. The temperature dependence of D T for diffusion of rubrene in SB is compared with that of the viscosity and the dielectric relaxation time τ D of SB. The temperature dependence of D T is weaker than that of T/η for T<1.2T g but tracks the reciprocal of the dielectric relaxation time 1/τ D for 1.05T g<T<1.21T g. The translational diffusion coefficient at T g is enhanced by a factor of ≈ 2.5×10 2 over the value predicted by the Stokes-Einstein equation. The decoupling of probe diffusion from the viscosity is characterized by a scaling law, D T∼η -ξ, with ξ=0.729.
| Original language | English (US) |
|---|---|
| Article number | 014510 |
| Journal | Journal of Chemical Physics |
| Volume | 124 |
| Issue number | 1 |
| DOIs | |
| State | Published - 2006 |
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ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
Cite this
Enhanced translational diffusion of rubrene in sucrose benzoate. / Rajian, Justin Rajesh; Huang, Wei; Richert, Ranko; Quitevis, Edward L.
In: Journal of Chemical Physics, Vol. 124, No. 1, 014510, 2006.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Enhanced translational diffusion of rubrene in sucrose benzoate
AU - Rajian, Justin Rajesh
AU - Huang, Wei
AU - Richert, Ranko
AU - Quitevis, Edward L.
PY - 2006
Y1 - 2006
N2 - The translational diffusion of rubrene in the fragile molecular glass former, sucrose benzoate (SB) (fragility index m≈94), has been studied from T g+6 K to T g+71 K(T g=337 K) by using the technique of holographic fluorescence recovery after photobleaching. In the temperature range of the measurements, the translational relaxation functions were observed to decay exponentially, indicating that Fick's law of diffusion governs the translational motion of rubrene in sucrose benzoate. The value of the translational diffusion coefficient D T obtained from the 1/e time of the translational relaxation function varied from 5.3×10 -15 cm 2 s -1 at 343 K to 5.0×10 -9 cm 2 s -1 at 408 K. The temperature dependence of D T for diffusion of rubrene in SB is compared with that of the viscosity and the dielectric relaxation time τ D of SB. The temperature dependence of D T is weaker than that of T/η for T<1.2T g but tracks the reciprocal of the dielectric relaxation time 1/τ D for 1.05T g<T<1.21T g. The translational diffusion coefficient at T g is enhanced by a factor of ≈ 2.5×10 2 over the value predicted by the Stokes-Einstein equation. The decoupling of probe diffusion from the viscosity is characterized by a scaling law, D T∼η -ξ, with ξ=0.729.
AB - The translational diffusion of rubrene in the fragile molecular glass former, sucrose benzoate (SB) (fragility index m≈94), has been studied from T g+6 K to T g+71 K(T g=337 K) by using the technique of holographic fluorescence recovery after photobleaching. In the temperature range of the measurements, the translational relaxation functions were observed to decay exponentially, indicating that Fick's law of diffusion governs the translational motion of rubrene in sucrose benzoate. The value of the translational diffusion coefficient D T obtained from the 1/e time of the translational relaxation function varied from 5.3×10 -15 cm 2 s -1 at 343 K to 5.0×10 -9 cm 2 s -1 at 408 K. The temperature dependence of D T for diffusion of rubrene in SB is compared with that of the viscosity and the dielectric relaxation time τ D of SB. The temperature dependence of D T is weaker than that of T/η for T<1.2T g but tracks the reciprocal of the dielectric relaxation time 1/τ D for 1.05T g<T<1.21T g. The translational diffusion coefficient at T g is enhanced by a factor of ≈ 2.5×10 2 over the value predicted by the Stokes-Einstein equation. The decoupling of probe diffusion from the viscosity is characterized by a scaling law, D T∼η -ξ, with ξ=0.729.
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U2 - 10.1063/1.2151898
DO - 10.1063/1.2151898
M3 - Article
VL - 124
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 1
M1 - 014510
ER -