| Autor: | Narayan Sahoo, W. Kreische, S. Swingle Nunes, Shukri Sulaiman, M. Frank, K. Bonde Nielsen, T. P. Das, K. Bharuth-Ram |
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| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | Hyperfine Interactions. :151-155 |
| DOI: | 10.1023/a:1017042432510 |
| Popis: | The Hartree-Fock cluster procedure was used to obtain the associated electronic distributions for 19F* (I = 5/2, E x = 197 KeV excited nuclear state of the 19F atom) at possible sites in crystalline Si, Ge and diamond and to calculate nuclear quadrupole coupling constants v Q and the asymmetry parameter η of the electric field gradient at the modelled sites. Lattice relaxation effects have been incorporated by employing a geometry optimization method to obtain minimum energy configurations for the clusters modelling each site. The intrabond (IB), antibonding (AB) and substitutional (S) sites in the bulk and the atop site on the surface were studied. From a comparison with v Q and η values observed in time differential perturbed angular distribution (TDPAD) measurements we were able to identify the high frequency component in Si and Ge with 19F* at the intrabond site. In diamond two high frequency components are observed. These are identified with 19F* at intrabond and substitutional sites. For the low frequency site in Si and Ge the assignment is made to 19F* implants at dangling bonds in the bulk resulting from implantation damage. In diamond none of the sites studied could provide lower frequency nuclear quadrupole parameters close to the observed ones. |
| Databáze: | OpenAIRE |
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