Cathodoluminescence from ‘giant’ platelets, and of the 2·526 eV vibronic system, in type Ia diamonds

The spectrum of the yellow cathodoluminescence emitted by ‘giant’ platelets in diamond is shown to be a featureless broad band superimposed on the shortwavelength tail of the well-known infrared luminescence from platelets. ‘Giant’ platelets are definitely not associated with the H3 system as has been suggested earlier. Also, strongly polarized emission in a vibronic band with a zero-phonon line at 490·7 nm (2·526 eV) has been observed to originate at regions of diamond that are plastically deformed. The 490·7 nm system has also been observed in volume distributions in growth bands.