Analysis of oxygen shell splitting in hydrothermally grown single crystal ThO sub(2)(200)

• Published in: Physica status solidi. PSS-RRL. Rapid research letters Vol. 9; no. 11; pp. 668 - 672
• Main Authors: Kelly, T D, Petrosky, J C, McClory, J W, Mann, J M, Kolis, J W
• Format: Journal Article
• Language: English
• Published: 01-11-2015
• Subjects: Fine structure; Hypercubes; Interstitials; Point defects; Single crystals; Splitting; Stabilization; X-rays
• ISSN: 1862-6254; 1862-6270
• DOI: 10.1002/pssr.201510235

Single crystals of ThO sub(2) have been synthesized using hydrothermal growth and studied using the X-ray absorption fine structure (XAFS) technique. The extended X-ray absorption fine structure (EXAFS) has been extracted from the XAFS and analyzed using a novel, computational Latin hypercube sampling method. The methodology not only confirms the expected space group and crystal structure, it also identifies the origin of a previously reported split O shell. Since EXAFS is a local order analysis technique, the O shell splitting is identified as an O atom occupying an interstitial site. This result is significant for examining O super(2-) transport in a ThO sub(2) matrix and corroborating research indicating partial Th 5f occupancy that is similar to hyper-stoichiometric UO sub(2+x) compounds. ( copyright 2015 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim) Extended X-ray photoemission fine structure data of hydrothermally synthesized ThO sub(2) has been interpreted. The data analysis included developing a novel Latin hypercube analysis tool used to identify a point defect structure, agreeing with recent experimental and theoretical research. Results are important to the understanding of the subtle role of 5f electrons in ThO sub(2) influencing O migration applications (e.g. solid state electrolytes) and future studies of mixed Th sub(x)U sub(y)O sub(2) oxide fuel stabilization.