High-energy XAFS study of molten terbium trichloride mixtures

Numakura, Masahiko; Okamoto, Yoshihiro  ; Yaita, Tsuyoshi; Shiwaku, Hideaki   ; Suzuki, Shinichi; Kobayashi, Toru ; Akutsu, Kazuhiro; Matsuura, Haruaki*

The high energy XAFS using K-absorption edge is very effective to obtain information on behavior of small amount of rare earth elements in molten chlorides. In the present study, we performed the XAFS measurement to obtain the local structure change for molten TbCl and the mixture of 40% TbCl with LiCl-KCl eutectic, 15% TbCl with LiCl-KCl eutectic and 1.5% TbCl with LiCl-KCl eutectic. We found that as the concentration of TbCl is lower, the coordination number decrease a little and become near 6 but the nearest Tb-Cl distance is almost same. In addition, we found that Debye-Waller factor become very small. We also performed molecular dynamics simulation to obtain the information of structure change. This simulation showed the intense structure change occurs at vicinity of 25% TbCl with LiCl-KCl eutectic. Its simulation result accorded with this XAFS experiment result.