The Li and Na trapped hole centres in MgO, CaO and SrO are studied with the periodic ab initio Hartree-Fock program CRYSTAL by using the supercell approach. A 64 atom supercell has been used that, in a preliminary investigation on the Li-MgO system, has been shown to be large enough to reduce the defect-defect interaction to negligible values. The metal ion M+ = Li+, Na+ and its first nearest neighbours (six oxygen ions) have been allowed to relax. In all the cases the hole is localized on an oxygen ion (O-) and M+ and O- relax in opposite directions. The calculated geometry after relaxation and the hyperfine and quadrupolar coupling constants are in reasonable agreement with data from ENDOR experiments.
Trapped-hole centres containing lithium and sodium in MgO, CaO and SrO. An ab initio supercell study
ORLANDO, Roberto;DOVESI, Roberto
1998-01-01
Abstract
The Li and Na trapped hole centres in MgO, CaO and SrO are studied with the periodic ab initio Hartree-Fock program CRYSTAL by using the supercell approach. A 64 atom supercell has been used that, in a preliminary investigation on the Li-MgO system, has been shown to be large enough to reduce the defect-defect interaction to negligible values. The metal ion M+ = Li+, Na+ and its first nearest neighbours (six oxygen ions) have been allowed to relax. In all the cases the hole is localized on an oxygen ion (O-) and M+ and O- relax in opposite directions. The calculated geometry after relaxation and the hyperfine and quadrupolar coupling constants are in reasonable agreement with data from ENDOR experiments.
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