¹A. A. Shiryaev,²A. V. Fisenko,³L. F. Semjonova,⁴A. A. Khomich,⁵I. I. Vlasov
¹Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia
²Institute of Ore Deposits, Petrography, Geochemistry and Mineralogy RAS, Moscow, Russia
³Vernadsky Institute of Geochemistry and Analytical Chemistry RAS, Moscow, Russia
⁴General Physics Institute RAS, Moscow, Russia
⁵National Research Nuclear University MEPhI, Moscow, Russia

Photoluminescence spectra show that silicon impurity is present in lattice of some nanodiamond grains (ND) of various chondrites as a silicon-vacancy (SiV) defect. The relative intensity of the SiV band in the diamond-rich separates depends on chemical composition of meteorites and on size of ND grains. The strongest signal is found for the size separates enriched in small grains; thus, confirming our earlier conclusion that the SiV defects preferentially reside in the smallest (≤2 nm) grains. The difference in relative intensities of the SiV luminescence in the diamond-rich separates of individual meteorites are due to variable conditions of thermal metamorphism of their parent bodies and/or uneven sampling of nanodiamond populations. Annealing of separates in air eliminates surface sp2-carbon; consequently, the SiV luminescence is enhanced. Strong and well-defined luminescence and absorption of the SiV defect is a promising feature to locate cold (<250 °C) nanodiamonds in space.

Reference
Shiryaev AA, Fisenko AV, Semjonova LF, Khomich AA, Vlasov II (2015) Photoluminescence of silicon-vacancy defects in nanodiamonds of different chondrites. Meteoritics&Planetary Science (in Press)
Link to Article [DOI: 10.1111/maps.12450]

Published by arrangement with John Wiley&Sons