Dynamics and Thermodynamics of Loosely Bound Molecules in Condensed Phases

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K05404
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Physical chemistry
• Research Institution: Osaka University (2016-2017); Institute of Physical and Chemical Research (2015)
• Principal Investigator: Suzuki Hal 大阪大学, 理学研究科, 招へい研究員 (50633559)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: リチウムイオン内包フラーレン / 水分子内包フラーレン / テラヘルツ分光法 / 熱容量

Outline of Final Research Achievements

Dynamics and thermodynamics of a Li+ ion and a H2O molecule encapsulated in a C60 cage were investigated by terahertz spectroscopy and calorimetry. In [Li+@C60](PF6-) crystal, Li+ ion was found to rotate in the C60 cage at room temperature. It was also revealed that the Li+ ion stops rotating below 100 K due to the localization in the cage, and is antiferroelectrically ordered below 24 K. In H2O@C60 crystal, H2O molecule was found to rotate even below 10 K. The rotational states are coupled with nuclear spin states, and the conversion from the triplet (ortho) state to the singlet (para) state was observed.
It is concluded that the loosely bound ions or molecules in spatially homogeneous spaces exhibit “free” rotation at high temperature even in the crystalline states. At low temperature, on the other hand, ions are likely to stop rotating but vibrate due to the localization, while molecules are likely to rotate even at very low temperature.

Free Research Field

凝縮系物理化学