Rm. Mineeva et al., Diamond crystals from Peoples Republic of China: An electron spin resonance and cathodoluminescence experimental study, GEOCHEM INT, 38(4), 2000, pp. 323-330
Electron spin resonance (ESR) and cathodoluminescence (CL) evidence on diam
onds from the Peoples Republic of China is reported. In addition to paramag
netic centers P1 and P2 that had been observed in China diamonds, the W7, W
21, N2, OK1, and O1 centers were identified by ESR spectra for the set of s
amples studied. The last two centers are regarded as oxygen-bearing. In the
CL spectra, in addition to broad bands at 440 and 530 nm (the latter being
related to boron centers), narrow bands were observed at 503 nm with phono
n repetitions (H3 center), 415 nm (P2 ESR center), 575 nm, and 490.7 nm, as
well as broad peaks at 720 and 920 nm. Characteristic narrow peaks were fr
equent on the background of the 720-nm broad peak; their appearance in synt
hetic diamond is assigned to the presence of nickel. An analysis of the app
earance and behavior of the centers that are observable in ESR and CL spect
ra showed a correlation between the type of defect, its concentration, and
abundance, on one hand, and the crystal morphology, mineralogy, and geochem
istry of the diamond, on the other. The ESR and CL characteristics of diamo
nds from various China deposits provide grounds to believe that the combina
tion of these parameters would aid in distinguishing diamonds from differen
t pipes. In some cases, this spectroscopic evidence would substantially rev
ise the prior genetic and geochemical ideas that were based on IR spectra a
nd CL patterns only and would make them more exact.