A novel method of producing atomic hydrogen and the active carbon species necessary for diamond chemical vapor deposition (CVD) has been demonstrated. This method starts with the generation of atomic chlorine from the thermal dissociation of molecular chlorine in a resistively heated graphite furnace at temperatures from 1300-1500-degrees-C. Atomic hydrogen and the carbon precursors are subsequently produced through rapid hydrogen abstraction reactions of atomic chlorine with molecular hydrogen and hydrocarbons at the point where they mix. It was found that the quality of the diamond deposits depends on both substrate temperatures and H2/Cl2 mole ratios. Substrate temperatures are found to be approximately 150-degrees lower than for a hydrogen/hydrocarbon hot filament system for similar growth rates.