Role of electron distribution of H and D atoms in hydrogen bond

本课题主要完成了以下四个方面的工作：1.利用中子非相干散射实验研究了KDP中氢原子的动力学性质，在此基础上提出了声子辅助非相干隧穿的新模型。我们还尝试用X射线衍射法研究KDP中氢原子的电子分布，但尚未得到可靠的结果。实验仍在继续.用新研制的低温Weissenberg照相机研究了K_3D（SO_4）_2的低温相结构。我们发现K_3D（SO_4）_2在相变的V点发生双q凝聚。我们还研究了（NH_4）_3H（SO_4）_2的连续相变。在这个系统中，我们发现不仅V点，Z点和Gamma点也是相变的相关对称位置.研究了新型氢键材料.一种是氢键结构玻璃，NH_4 I-KI混合体系。用中子非相干散射研究了NH_4离子运动的冻结。我们还进行了X射线散射实验来观察碘的运动。另一个体系是分子内氢键体系d-BrHPLN，我们发现该体系发生了质子化-无公度转变.发展了低温X射线实验技术，特别是低温Weissenberg照相技术。这种技术打开了广泛的可能性，找到弱卫星反射在倒易空间。

We have performed four different works on the research project as follows :1. Neutron incoherent scattering experiments were performed to investigate the dynamical properties of hydrogen atoms in KDP.New model called phonon assisted incoherent tunneling was proposed based on the present experiments. We also try to investigate the electron distribution of hydrogen atom in KDP by X-ray diffraction, but reliable results are not obtained yet. The experiments are still being continued.2. Structure of low temperature phase of K_3D(SO_4)_2 was examined by a newly developed low temperature Weissenberg camera. We found that double q condensation occurs at V-point on the phase transition of K_3D(SO_4)_2. We also studied the successive phase transition of (NH_4)_3H(SO_4)_2. In this system, we found that not only V-point but also Z-point and GAMMA-point are relevant symmetry positions for the phase transition.3. New category materials as hydrogen bonded system were studied. One is a structural glass by hydrogen bonding, NH_4I-KI mixed system. Neutron incoherent scattering was performed to investigate the freezing of NH_4 ion motion. We also performed X-ray scattering experiments to look iodine motion. Another system is the intramolecular hydrogen bond system, d-BrHPLN.We found this system took commensurate-incommensurate transition.4. Technique to perform low temperature X-ray experiments, especially low temperature Weissenberg photograph, was developed. This technique opens the wide possibility to find weak satellite reflections in a reciprocal space.