Dynamic Jahn-Teller distortions at trigonal optical centres in diamond

Abstract

Uniaxial stress measurements are reported on two commonly occurring radiation damage centres in diamond. Their zero-phonon lines, at 17380 and 23530 cm^-1; are shown to be electric-dipole transitions between E (ground) and A₁, or A₂, (excited) states at trigonal centres (C₃, C_3v of D_3d). Other non-degenerate states are found approximately 100 cm^-1 above the ground level. The data are consistent with dynamic Jahn-Teller distortions occurring in the ground states of the centres. On bringing together information on all the known degenerate electronic states at trigonal centres in diamond, two simple generalisations emerge for the occurrence of Jahn-Teller effects at these centres.