Interstitial defects in diamond: A quantum mechanical simulation of their EPR constants and vibrational spectra

Abstract

The local geometry, electronic structure, and vibrational features of three vicinal double interstitial defects in diamond, ICIC, ICIN, and ININ, are investigated and compared with those of three "simple" ⟨100⟩ interstitial defects, ICC, ICN, and INN, previously reported by Salustro et al. [Phys. Chem. Chem. Phys. 20, 16615 (2018)], using a similar quantum mechanical approach based on the B3LYP functional constructed from Gaussian-type basis sets, within a supercell scheme, as implemented in the CRYSTAL code. For the first time, the Fermi contact term and hyperfine coupling tensor B of the four open shell structures, ICIC, ICIN, ICC, and ICN, are evaluated and compared with the available experimental EPR data. For the two double interstitial defects, the agreement with experiment is good, whereas that for the single interstitials is found to be very poor, for which a likely reason is the incorrect attribution of the EPR spectra to uncertain atomic details of the microstructure of the samples. The infrared spectra of the three double interstitial defects exhibit at least two peaks that can be used for their characterization.

The Annealing Kinetics of Defects in CVD Diamond Irradiated by Xe Ions

“…This is confirmed by a variation in the migration energies with the fluence (Figure 9) and the very small values of extracted pre-factor parameters X in Table 1. This result needs further quantum mechanical calculations [42]. The decrease in the interstitial migration energy with the radiation fluence was observed earlier for Al 2 O 3 , MgO, and MgF 2 [33], and is a manifestation of the anomalous diffusion [33].…”

The Annealing Kinetics of Defects in CVD Diamond Irradiated by Xe Ions

“…Theoretical analysis of the experimental kinetics of the basic radiation defects (interstitialvacancy carbon Frenkel defects responsible for the absorption at 4.1 eV and 2.0 eV, respectively) in CVD diamond disks shows the migration energy of the interstitial ions as quite low, of the order of 0.2-0.4 eV. This result needs further quantum mechanical calculations [22]. The migration energy is predicted to decrease with the radiation fluence: the effect observed earlier for Al2O3, MgO, MgF2 [35].…”

“…The surface termination of freshly grown diamond depends on the available molecules during the growth process, which is typically hydrogen. However, these hydrogen atoms can be replaced by other elements such as oxygen, nitrogen, sulfur and even halogens by performing thermal, electrochemical or plasma treatments [21,22]. Oxygen-and nitrogen terminated diamond are commonly employed as well for further functionalization via silanization, esterification or amidation reactions.…”