[en] To date, there is no universally recognized notion of diamond structure formation from the gas phase. The set of fragments determining this process differs for different methods of activation. Information on elementary processes of the interaction of hydrogen and hydrocarbon molecules with a surface for activation and deposition can be found in the literature, but it is scarce. Scientific problems of thermal activation relate not only to carbon structure synthesis; the description of non-equilibrium processes in channel flows with heterogeneous chemical reactions has unquestionable importance. In this review, the modern state of studies on the interaction of hydrogen and methane molecules and their fragments with high-temperature tungsten surfaces and diamond surfaces at temperatures close to 1300 K is considered, and accessible results are presented. (instruments and methods of investigation)