The effect of a crystal field on density functional calculations of positron lifetimes in alkali halides

Academic Article


  • A first-principles theoretical investigation of positron annihilation in alkali halide crystals is carried out using a simplified cluster-embedding scheme. The system is represented as a halide-centred cluster with basis functions only at the centre. The rest of the crystal is modelled in two ways: (i) point ions located at lattice positions; and (ii) frozen-orbital ions derived from an energy band calculation for the pure crystal. Calculations for both models are carried out within the self-interaction-corrected local spin-density approximation and by incorporating an electron-positron correlation functional. The effect of the model assumed on the calculated positron lifetimes is analysed by demonstrating the sensitivity of the results to the inclusion of the Madelung potential. A comparison of positron lifetimes of the ground state of the positron to lifetime components identified in experimental work on lithium and sodium halide systems is made.
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    Digital Object Identifier (doi)

    Author List

  • Kim K; Harrison JG
  • Start Page

  • 3583
  • End Page

  • 3600
  • Volume

  • 9
  • Issue

  • 17