EPR and double resonances in study of diamonds and nanodiamonds

Abstract

© 2019 Elsevier Inc. Nitrogen and nitrogen-vacancy paramagnetic defects in crystals and nanocrystals of diamonds, as well as paramagnetic centers localized on the surface of nanoparticles, were studied by electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) methods. The spin optical polarization effect is explained qualitatively by the action of nondiagonal components of the Zeeman interaction, leading to mixing of the wave functions of the ground state. Relaxation-time dependencies are shown for NV− centers. High-frequency (94 GHz) EPR studies of nanodiamonds resolved spectrally three components related to defects in the crystalline core of a nanoparticle, on its surface and in the surface layer. Examples of ENDOR application for control of diamond nanoparticles surface modification by hydrogen and fluoride are demonstrated.