Quantitative analysis of dynamics in strongly-correlated molecular liquid SeBr

強い配向相関を有する分子性液体SeBrのダイナミクスに関する定量的解析

島倉 宏典; 川北 至信  ; 稲村 泰弘  ; 菊地 龍弥  ; 上野 広樹; 中村 充孝   ; 河村 聖子   ; 柴田 薫*; 新井 正敏; 武田 信一*

Shimakura, Hironori; Kawakita, Yukinobu; Inamura, Yasuhiro; Kikuchi, Tatsuya; Ueno, Hiroki; Nakamura, Mitsutaka; Kawamura, Seiko; Shibata, Kaoru*; Arai, Masatoshi; Takeda, Shinichi*

Se-Br system has a deep eutectic point around the equi-atomic composition. Earlier neutron diffraction experiments suggested that, in eutectic Se-Br, molecules of Br-Se-Se-Br exhibit a strong inter-molecular correlation where Se-Se bond is parallel to that in neighboring molecules. To reveal structural relaxation process in liquid SeBr, QENS measurements were performed at three temperatures by utilizing cold-neutron disk-chopper spectrometer installed at BL14 beamline in MLF of J-PARC. Multi Ei technique was applied so that incident neutron energies were 3.13, 7.72 and 41.83 meV. It is found that QENS signals with 7.72 meV can be well fitted by sum of two Lorentzian components corresponding to slow and fast relaxation modes, respectively. Temperature dependence of the magnitude of each Lorentzian function and the half width at half maximum show that the slow mode depends on the molecular thermal agitation and fast mode depends on the inter-molecular correlation.