We have investigated theoretically the possibility that the CH2CH(a (4)A(')) radical can generate the CH2CHO+(X (1)A(')) ion upon collisions with O(P-3). We have concluded that this is very unlikely because the minimum of the ground-state potential-energy surface of the ion is at about the same level as the potential energy of the asymptotic CH2CH(a (4)A('))+O(P-3) fragments. In addition the Franck-Condon factors should not be favorable because of a drastic change in the geometry of the ion. (C) 2003 American Institute of Physics.