| Autor: |
Ackerman M; Department of Chemistry, University of Chicago, IL 60637, USA., Kim E; Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, NV 89154, USA. kimej@physics.unlv.edu., Weck PF; Sandia National Laboratories, Albuquerque, NM 87185, USA., Chernesky W; Remote Sensing Laboratory-Nellis Air Force Base, Las Vegas, NV 89191, USA., Czerwinski KR; Department of Chemistry, University of Nevada, Las Vegas, NV 89154, USA. |
| Abstrakt: |
Atomistic investigations of crystalline scheelite, CaWO 4 , and 99 Tc-bearing scheelite, CaWO 4 :Tc, have been carried out using density functional theory. The lattice constants, bulk modulus, and volume compression data of CaWO 4 have been calculated and compared with experimental data, with a focus on predictive understanding of 99 Tc incorporation in CaWO 4 . Defect formation energies have been computed for several possible interstitial (I) and substitutional (S) sites of 99 Tc in CaWO 4 . Both I(O h ) and S(W) sites were found to be energetically favourable for Tc doping. X-ray diffraction (XRD) spectra for each 99 Tc defect type have been simulated to help interpret the complex experimental XRD patterns. This work on CaWO 4 :Tc provides insights into materials generated during nuclear weapons testing and useful spectral signatures for nuclear forensics. |
