Uniaxial stress splitting of E to E transitions at trigonal centres in cubic crystals: the 594 nm band in diamond

E to E electric-dipole transitions at trigonal centres in cubic crystals are considered. Expressions for the intensities and energies of the stress-split components of the transition are tabulated for (001), (111) and (110) stress axes. As an example, uniaxial stress data for the 594 nm line in a diamond are reported. They are shown to be consistent with an E to E (trigonal) transition, the ground E state interacting under stress with a non-degenerate state approximately 100 cm -1 above it.