Phonon Anharmonicity of PdO Studied by Raman Spectrometry
Phonon Anharmonicity of PdO Studied by Raman Spectrometry
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DOI：
10.1021/acs.jpcc.5b07652
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发表时间：
2015-09
影响因子：
3.7
通讯作者：
Zhouying Zhao;J. Elwood;M. Carpenter
中科院分区：
文献类型：
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作者：
Zhouying Zhao;J. Elwood;M. Carpenter
在298 ~ 973 K温度范围内测量了氧化钯（PdO）的拉曼光谱。一阶散射的B1 g和Eg声子模式显示出显着的频率和线宽的温度依赖性。声子行为的模型，考虑从三次和四次声子衰变过程的热膨胀相关的准谐性和明确的晶格非谐性的贡献，以及描述。与谱线位移的准谐性相比，B1 g模的显式非谐性相对较小，三次非谐性领先于四次项。Eg模具有较小的线位移，其主要遵循四次声子衰减机制，而立方贡献被热膨胀效应抵消。三次非谐性主要占主导地位的线加宽与更突出的四次效应负责更大的Eg模式的加宽。多个潜在的不对称三次和四次非谐波衰减通道，包括下转换…
Raman spectra were measured for palladium oxide (PdO) at temperatures from 298 to 973 K. The first-order scattering B1g and Eg phonon modes show prominent frequency and line width dependencies on temperature. The phonon behaviors are described well by a model considering contributions from thermal expansion related quasiharmonicity and explicit lattice anharmonicity from both cubic and quartic phonon decay processes. Compared to the quasiharmonicity for the line shift, the explicit anharmonicity is found to be relatively smaller for the B1g mode with the cubic anharmonicity leading the quartic term. The Eg mode has a smaller line shift which mostly follows a quartic phonon decay mechanism while the cubic contribution is canceled by thermal expansion effects. The cubic anharmonicity dominates mostly the line broadening with more prominent quartic effects responsible for the larger broadening of the Eg mode. Multiple potential asymmetric cubic and quartic anharmonic decay channels including down-conversion ...