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Many-electron calculations based on a generalized Hubbard Hamiltonian for electronic states of the diamond vacancies are reported. The model does not use the configuration interaction (CI) method and proper tetrahedral symmetry and spin properties of the defect are included in the Hamiltonian. Atomic orbital bases are introduced for the Hamiltonian calculation. Excited states of both neutral and negatively charged vacancies in diamond are calculated. The calculated values for the experimentally observed first dipole transition energies of the vacancies in diamond, GR1 and ND1 bands, are in good agreement with experiment. To obtain these results, we used a semi-empirical Hamiltonian parameter. The position of the low-lying 3T1 state was found to be 260 meV above the ground state, which is consistent with experimental expectations. In addition to the energy spectrum, the model gives all eigenfunctions of the vacancies, which have not been calculated before. This model has high potential for further applications in point defects of diamond and other semiconductors. (Â© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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