Netsu Sokutei, 28 (4), p. 164, (2001)



Deuteration Induced Phase Transitions in Zero-dimensional Hydrogen Bonded Crystals M3H(XO4)2

0次元水素結合結晶M3H(XO4)2について,熱容量測定と粉末中性子回折の結果か ら,重水素化物の相転移が水素結合上の重水素原子の位置に関する秩序・無秩序転移 であること,重水素誘起相転移の起源がプロトントンネリングにより理解できること を示した。
The origin of deuteration induced phase transitions in zero-dimensional hydrogen bonded crystals M3H(XO4)2 is discussed based on the experimental results on the heat capacity and the neutron powder diffraction. The phase transitions in the deuterated compounds are of order-disorder type with respect to the deuteron position on the hydrogen bond. Proton tunnelling plays an essential role in this large isotope effect.