title: The lattice stiffening transition in UO2single crystals.
abstract: The effective Debye temperatures ([Formula: see text]) of the surface region of UO2single crystals, prepared by the hydrothermal synthesis technique, were obtained from temperature-dependent x-ray photoemission in the temperature range of 300 K-623 K. A lattice stiffening transition, characterized by different regions of different effective Debye temperature, 500  ±  59 K below 475 K and 165  ±  21 K above 475 K is identified. A comparison of the temperature dependence of the effective UO2Debye temperature, with the changes in the lattice expansion coefficient for UO2, support strong lattice-phonon interaction arising from the Jahn-Teller distortion.
authors.affiliation: Department of Engineering Physics, Air Force Institute of Technology, 2950 Hobson Way, Wright-Patterson Air Force Base, OH 45433-7765, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Young
authors.forename: James
authors.initials: J
authors.lastname: Petrosky
authors.forename: J Matthew
authors.initials: JM
authors.lastname: Mann
authors.forename: Eric M
authors.initials: EM
authors.lastname: Hunt
authors.forename: David
authors.initials: D
authors.lastname: Turner
authors.forename: Peter A
authors.initials: PA
authors.lastname: Dowben