## Abstract

A nonempirical first-principles energy-band calculation for diamond has been used to calculate the optical absorption expressed as the imaginary part of the complex dielectric function ε2(ω) in the random-phase approximation. The use of k→-dependent transition-probability matrix elements calculated from the Bloch linear-combination-of-atomic-orbitals wave functions is found to significantly improve agreement of the calculated ε2(ω) with experiment, as compared to the results obtained with averaged matrix elements. Within the statistical exchange one-electron band model Hamiltonian and the random-phase approximation to the dielectric function, we find good agreement with experiment for the magnitude and position of the main peak and general shape of ε2(ω) over a large energy range without any empirical adjustment of the calculation. There is structure in the low-energy region which is not reproduced by our treatment, suggesting inherent deficiencies of the band model and/or limitations of the theoretical expression for ε2(ω).

Original language | English (US) |
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Pages (from-to) | 3950-3956 |

Number of pages | 7 |

Journal | Physical Review B |

Volume | 6 |

Issue number | 10 |

DOIs | |

State | Published - Jan 1 1972 |

## ASJC Scopus subject areas

- Condensed Matter Physics