Abstract
Identification of intermediate and final products of the chemical reaction that produces nanodiamond particles is a key factor in understanding its mechanism. In this work different nanodiamond samples were studied before and after chemical cleaning by X-ray photoelectron and Auger spectroscopy. It was found that the chemical state of carbon atoms is the same before and after chemical cleaning. We find that the carbon atoms are sp3-bonded inside nanodiamond particles and have a new, unique chemical state on the surfaces. The latter differs significantly from sp2- and sp3-bonded carbon and can be figured as the valence band near the Fermi level being occupied by three electrons.