Abstract
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 ...
Published Version
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