About this Abstract |
Meeting |
MS&T22: Materials Science & Technology
|
Symposium
|
Ceramics for a New Generation of Nuclear Energy Systems and Applications
|
Presentation Title |
Modeling Vibrational Modes in Raman Spectra of ThO2 |
Author(s) |
Saqeeb Adnan, Joshua Ferrigno, Erika Nosal, Chao Jiang, Marat Khafizov |
On-Site Speaker (Planned) |
Saqeeb Adnan |
Abstract Scope |
Vibrational properties are key to understanding thermal transport in thorium dioxide (ThO2). Raman spectroscopy provides a convenient approach to characterize selected vibrational modes in fluorite oxides. While analysis of Raman spectra of the irradiated fluorite oxides is becoming a common characterization tool, the origin of the irradiation-induced defect peaks remains controversial. We present a first-principles calculation based on defect symmetry to isolate the contribution of different defects to experimentally observed Raman peaks. The analysis focuses on isolating specific atomic bonds contributing to the emergence of the Raman peaks. In particular, the Longitudinal Optical (LO) peak, that has been commonly attributed to the presence of oxygen vacancy is assigned to a stretching motion of the O-O bond nearest to the vacancy site. This Raman peak analysis provides better insight into the origin of the different vibrational modes and opens up possibilities for the validation of microstructure evolution models in irradiated fluorites. |