Potential Energy Surfaces for the Reaction Al + O₂→ AlO + O

Abstract

Potential energy surfaces for the reaction Al + O 2 → AlO + O have been calculated with the multireference configuration interaction (MRCI) method using molecular orbitals derived from the complete active space selfconsistent field (CASSCF) calculations. The end-on geometry is the most favourable for the reaction to take place. The small reaction barrier in the present calculation (0.11 eV) is probably an artefact related to the ionicneutral avoided crossing. The charge analysis implies that the title oxidation reaction occurs through a harpooning mechanism. Along the potential energy surface of the reaction, there are two stable intermediates of AlO 2 (C ∞v and C 2v ) at least 2.74 eV below the energy of reactants. The calculated enthalpy of the reaction (−0.07 eV) is in excellent agreement with the experimental value (−0.155 eV) in part due to the fortuitous cancellation of errors in AlO and O 2 calculations.

Correlation Study of the Spin–Orbit State-Resolved Scattering of Al(2P) in Oxidation Reaction and Nonreactive Collision

“…The oxidation dynamics of the Al atom, an important process with applications in combustion and rocket propellants, has been studied experimentally and theoretically over the past 50 years. − The Al­( 2 P) atom has two spin–orbit split Al­( 2 P 1/2 ) and Al­( 2 P 3/2 ) states with the energy difference of 112 cm –1 . Chen et al .…”