Hydration of oxygen-deficient metal oxides causes filling of oxygen vacancies and formation of hydroxyl groups with interstitial structural protons, rotating around the oxygen in localized motion. Thermal activation from 500 to 800 K triggers delocalization of the protons by jumping to adjacent oxygen ions, constituting proton conductivity. We report quantitative analyses of proton and lattice dynamics by neutron-scattering data, which reveal the interaction of protons with the crystal lattice and proton-phonon coupling. The motion for the proton trapped in the elastic crystal field yields Eigen frequencies and coupling constants, which satisfy Holstein's polaron model for electrons and thus constitutes first experimental evidence for a proton polaron at high temperature. Proton jump rates follow a polaron model for cerium-oxygen and hydroxyl stretching modes, which are thus vehicles for proton conductivity. This confirms that the polaron mechanism is not restricted to electrons, but a universal charge carrier transport process.

中文翻译：

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在水合金属氧化物质子导体中质子极化子的实验中子散射证据。

缺氧金属氧化物的水合导致氧空位的填充和带有间隙结构质子的羟基的形成，质子在局部运动中围绕氧旋转。从500 K到800 K的热活化通过跳到相邻的氧离子来触发质子的离域，从而构成质子传导性。我们通过中子散射数据报告质子和晶格动力学的定量分析，揭示了质子与晶格和质子-声子耦合的相互作用。质子在弹性晶体场中的运动产生本征频率和耦合常数，满足电子的霍尔斯坦极化子模型，因此构成了高温下质子极化子的第一个实验证据。质子跳跃速率遵循用于铈-氧和羟基拉伸模式的极化子模型，因此是质子传导性的媒介。这证实了极化子机制不限于电子，而是通用的载流子传输过程。