TY - JOUR
T1 - Nitrogen concentration and anisotropic effects on the EPR spectra of natural diamonds
AU - Litvak, Ira
AU - Cohen, Haim
AU - Anker, Yaakov
AU - Ruthstein, Sharon
N1 - Funding Information: SR acknowledges the support of an Israel Ministry of Science grant (#3-14330). We would like to acknowledge Mr Avner Cahana from the Israeli Diamond Bourse for providing the diamonds and helpful discussions. Publisher Copyright: © The Royal Society of Chemistry.
PY - 2021/5/21
Y1 - 2021/5/21
N2 - Paramagnetic centers in diamonds are affected by nitrogen atom contamination in the lattice. This study aimed to better understand the nitrogen concentration and anisotropy impact on the EPR (electron paramagnetic resonance) spectrum of natural diamonds (i.e. appropriate for color enhancement treatments). All the diamonds used were natural either colorless or faintly colored (D-M color range), which were selected according to the targeted final color post-treatment: Green, blue, pink, orange, and yellow. Their paramagnetic centers were studied using EPR spectroscopy at various microwave power levels and evaluated for nitrogen concentration via FTIR spectroscopy. The results show a correlation between nitrogen concentrations and spin concentrations in all the pretreated diamonds, whereas the most abundant fast-relaxing paramagnetic center is similar to the C-centered radical. In addition, the hyperfine interaction anisotropy of the paramagnetic centers of nearby nitrogen atoms was found to be valid for pretreated green, pink, and orange diamonds. By clarifying the final structure of the treated fancy diamonds, which are visibly affected by adjacent nitrogen atoms, this study contributes to the refinement of colorless natural diamond selection for color enhancement.
AB - Paramagnetic centers in diamonds are affected by nitrogen atom contamination in the lattice. This study aimed to better understand the nitrogen concentration and anisotropy impact on the EPR (electron paramagnetic resonance) spectrum of natural diamonds (i.e. appropriate for color enhancement treatments). All the diamonds used were natural either colorless or faintly colored (D-M color range), which were selected according to the targeted final color post-treatment: Green, blue, pink, orange, and yellow. Their paramagnetic centers were studied using EPR spectroscopy at various microwave power levels and evaluated for nitrogen concentration via FTIR spectroscopy. The results show a correlation between nitrogen concentrations and spin concentrations in all the pretreated diamonds, whereas the most abundant fast-relaxing paramagnetic center is similar to the C-centered radical. In addition, the hyperfine interaction anisotropy of the paramagnetic centers of nearby nitrogen atoms was found to be valid for pretreated green, pink, and orange diamonds. By clarifying the final structure of the treated fancy diamonds, which are visibly affected by adjacent nitrogen atoms, this study contributes to the refinement of colorless natural diamond selection for color enhancement.
UR - http://www.scopus.com/inward/record.url?scp=85106017862&partnerID=8YFLogxK
U2 - https://doi.org/10.1039/d0ce01653e
DO - https://doi.org/10.1039/d0ce01653e
M3 - Article
SN - 1466-8033
VL - 23
SP - 3453
EP - 3459
JO - CrystEngComm
JF - CrystEngComm
IS - 19
ER -