RATE-CONSTANT CALCULATIONS FOR ATOM-DIATOM REACTION INVOLVING AN OPEN-SHELL ATOM AND A MOLECULE IN A SIGMA-ELECTRONIC-STATE - APPLICATION TO THE REACTION AL(P-2(1 X-3-SIGMA(-)(G))-]ALO(X-2-SIGMA(+))+O(P-3(2,1,0))/

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 adiaba tic 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 spinorbit basis set of each reactant for the Al( P-2(1/2,3/2)) + O-2(X (3)Sigma(g)(-)) reaction and used within the ACC SA method to calculate the temperature dependence of the rate constant in the range 15-300 K. In the limit of zero temperature, the reactivi ties of the two spin-orbit states of the aluminium atom, Al(P-2(1/2)) and Al(P-2(3/2)), towards the O-2 molecule are demonstrated to be diff erent and analytical formulae for the rate constants are obtained as a function of temperature.