VIBRATIONAL AND ELECTRONIC EXCITATIONS IN ISOTOPICALLY CONTROLLED DIAMONDS

Lattice vibrations of isotopically controlled single crystals of diamo nd (C-12(1-x) C-13(x), 0 less than or equal to x less than or equal to 1) are investigated with Raman, Brillouin, and Fourier transform infr ared spectroscopy. The variation of the zone center optical phonon fre quency and elastic moduli in the context of the virtual crystal approx imation and zero-point motion; critical point frequencies as manifeste d in the two-phonon Raman and infrared spectra are addressed in these studies. The electronic infrared and Raman spectra of holes bound to s ubstitutional boron accepters in isotopically controlled diamonds show : (1) the Lyman transitions in which the bound states manifest host-re lated-self-energy shifts; (2) the spin-orbit splitting (Delta') of the 1s ground state into 1s(p(3/2)) and 1s(p(1/2)), 1s(p(1/2)) being ther mally populated; (3) a direct observation of the 1s(p(3/2)) --> 1s(p(1 /2)) transition as an electronic Raman at Delta', together with its is otopic effects.