ISOTOPIC-DISORDER INDUCED RAMAN-SCATTERING IN DIAMOND

We compare the Raman spectra of three isotopically disordered diamond samples with that of natural diamond. The isotopically disordered samp les exhibit disorder induced Raman-activated features on the low energ y tail of the zone center optical phonon. The strength of these additi onal scattering depends on the degree of disorder. The experimental sp ectra are compared with calculations using the coherent-potential-appr oximation (CPA) and also with lowest order perturbation theory. Good a greement with experiments is found especially for the CPA results.