title: Technetium incorporation in scheelite: insights from first-principles.
abstract: Atomistic investigations of crystalline scheelite, CaWO4, and99Tc-bearing scheelite, CaWO4:Tc, have been carried out using density functional theory. The lattice constants, bulk modulus, and volume compression data of CaWO4have been calculated and compared with experimental data, with a focus on predictive understanding of99Tc incorporation in CaWO4. Defect formation energies have been computed for several possible interstitial (I) and substitutional (S) sites of99Tc in CaWO4. Both I(Oh) and S(W) sites were found to be energetically favourable for Tc doping. X-ray diffraction (XRD) spectra for each99Tc defect type have been simulated to help interpret the complex experimental XRD patterns. This work on CaWO4:Tc provides insights into materials generated during nuclear weapons testing and useful spectral signatures for nuclear forensics.
authors: Department of Chemistry, University of Chicago, IL 60637, USA.
authors: Matthew
authors: M
authors: Ackerman
authors: Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, NV 89154, USA. kimej@physics.unlv.edu.
authors: Eunja
authors: E
authors: Kim
authors: Sandia National Laboratories, Albuquerque, NM 87185, USA.
authors: Philippe F
authors: PF
authors: Weck
authors: Remote Sensing Laboratory-Nellis Air Force Base, Las Vegas, NV 89191, USA.
authors: Wendy
authors: W
authors: Chernesky
authors: Department of Chemistry, University of Nevada, Las Vegas, NV 89154, USA.
authors: Kenneth R
authors: KR
authors: Czerwinski