氢化锆(ZrH1.7)和钯氢(PdH0.7)光学声子的温度效应

在本院重水堆旁的铍过滤探测器中子非弹性散射谱仪上,对氢化锆(ZrH_1.7)(含碳0.2％)和钯氢(PdH_0.7)两种金属氢化物在室温和低温(97K)两种温度下,分别测定了光学声子能谱。结果表明:氢化锆的光学声子能级是等间距的,能级宽度基本上不随温度变化,即光学声子的非谐性是微弱的,较好地遵从爱因斯坦的谐振模型;而钯氢的第二个光学声子能级间距大于第一个能级间距约8meV,并且光学声子能级的宽度从室温下的38meV变化到低温(97K)下的20meV,这表明对钯氢的超导性起决定作用的光学声子,存在较明显的非谐性。 关键词：

TEMPERATURE EFFECTS OF OPTICAL PHONON FOR ZrH1.7 AND PdH0.7

The optical phonon spectra for ZrH_1.7 (containing 0.2% C) and PdH_0.7 are measured at room temperature and low temperature (97 K) -with beryllium filter detector spectrometer adjacent to the heavy water pile in the Institute off Atomic Energy. The results show that: (1) Optical phonon Energy Level for ZrH_1.7 is equal essentially spacing, the width of energy level essentially does not change with T i.e. the anharmonicity of optical phonon. is weak and it obeys Einstein harmonic model. (2) The second optical phonon energy level spacing for PdH_0.7 is about 8 meV larger than that of the first level spacing, and the width of its optical phonon energy level changes from 38 meV at room temperature to 20 meV at 97 K. This means that the optical phonons which ply important role in supercondectivity of PdH_x exhibit significant anharmonicity.