Rate constant calculations for atom–diatom reaction involving an open-shell atom and a molecule in a Σ electronic state Application to the reaction Al(2P1/2,3/2)+O2(X3Σg-)→AlO(X2Σ+) +O(3P2,1,0)

Abstract

We present a short study of the influence of the open-shell nature of the reactants on the kinetics of the title reaction. We use the adiabatic capture centrifugal sudden approximation (ACCSA) method and a long-range potential comprising the sum of the quadrupole–quadrupole, spin–orbit and dispersion contributions. Matrix elements of this potential are evaluated in the spin–orbit basis set of each reactant for the Al(²P_1/2,3/2)+O₂(X³Σ_g^-) reaction and used within the ACCSA method to calculate the temperature dependence of the rate constant in the range 15–300 K. In the limit of zero temperature, the reactivities of the two spin–orbit states of the aluminium atom, Al(²P_1/2) and Al(²P_3/2), towards the O₂ molecule are demonstrated to be different and analytical formulae for the rate constants are obtained as a function of temperature.