Full-dimensional analytical potential energy surfaces (PESs) for the O(P-1) + C2H2 and O(P-3) + C2H2 reactions are presented. The PESs are constructed by fitting thousands of ab initio data points using permutationally invariant polynomials [5]. Electronic structure data are obtained within the restricted coupled cluster theory with single and double excitations with perturbative triple corrections and correlation consistent basis set of triple-zeta with diffuse functions. Motivated by experiments, formation of DOCC and cyclic DCCO at collision energies of 2.5-4 eV is examined using quasi-classical trajectory dynamics on the triplet surface. (C) 2013 Elsevier B.V. All rights reserved.