Details

Autor(en) / Beteiligte

• Kikuchi, Tatsuya
• Kawakita, Yukinobu
• Nakajima, Kenji
• Ohira-Kawamura, Seiko
• Inamura, Yasuhiro

Titel

Overall picture and details of diffusion dynamics for liquid benzene by quasielastic neutron scattering and mode distribution analysis

Ist Teil von

• Journal of molecular liquids, 2023-09, Vol.385, p.121868, Article 121868

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2023

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• •MDA, a model-free analysis method, was applied to QENS from liquid benzene.•Liquid benzene has three relaxation modes in total.•The intermediate relaxation mode is the three-dimensional reorientation with a jump.•The overall picture of diffusion of molecular liquids can be clarified with MDA. We investigated the diffusion dynamics of liquid benzene as a basic molecular liquid. Quasielastic neutron scattering (QENS) was utilized to elucidate the overall behavior of molecular diffusion in liquid benzene. Mode distribution analysis, which does not require specific model assumptions and can describe molecular dynamics by QENS as a distribution of Lorentz functions, revealed that the diffusion of benzene molecules is represented by three dynamic modes. The Q-dependencies of the scattering intensity and the relaxation time were analyzed using diffusion models constructed to match each dynamic mode. (1) The slowest mode is translational diffusion, described as continuous diffusion rather than jump diffusion. (2) The intermediate-speed mode is rotational diffusion, which is due to the three-dimensional reorientation of benzene molecules with a jump angle of approximately 90°. (3) The fastest mode involves local fluctuations, which may originate from translational oscillations and librations of the benzene crystal. The overall picture of the diffusion dynamics and characteristics of the individual modes were clarified without using a model, which is a new approach in the field of diffusion dynamics of molecular liquids.