Gas-surface thermochemistry and kinetics for aluminum particle combustion

Quantum chemical calculations have been used to investigate possible reactions on aluminum surfaces in the Al/H/C/O/N system. Transition states or barrierless reaction paths have been identified for essentially all feasible adsorption/desorption reactions in this system involving atoms and homonuclear diatomic molecules. Structures, energies, and vibrational frequencies for adsorbed species in this system are presented and compared to available experimental data. Thermodynamic data (standard enthalpy of formation) and kinetic data (forward and reverse energy barriers) are presented. These results provide a basis for the estimation of reaction rate parameters for this system using transition state theory (TST) and related unimolecular reaction rate theories, and thereby constructing a reaction mechanism useful for detailed chemical kinetic modeling of aluminum particle combustion in a propellant environment. In the few cases where previous experimental or theoretical results have been published, the present work is consistent with these studies.