Abstract <p>Computational methods of quantum chemistry were used to study the energy pathways of possible reactions of ammonia with hydrogen and oxygen atoms, as well as with the hydroxyl radical. The B3LYP, M062X, MP2 and CBS-QB3 methods were used to localize stationary points on the potential energy surface of the system containing the above reagents. A number of intermediate compounds formed during the interaction of ammonia with atoms and radicals were identified, and information on the structure and thermochemical parameters of the intermediates formed was obtained. Based on the calculation results, diagrams of the energy levels of the systems under consideration were constructed. The results obtained demonstrate the important role of the NH₃ + H, NH₃ + O and NH₃ + OH reactions in the processes of ammonia combustion.</p>