We present computational results of vibrationally enhanced positron annihilation in the e(+) + HCN/DCN collisions within a local complex potential model. Vibrationally elastic and inelastic cross sections and effective annihilation rates were calculated by solving a time-dependent complex-potential Schrodinger equation under the ab initio potential energy surface for the positron attached HCN molecule, [HCN; e(+)], with multi-component configuration interaction level (Kita and Tachikawa, 2014). We discuss the effect of vibrational excitation on the positron affinities from the obtained vibrational resonance features. (c) 2017 Elsevier B.V. All rights reserved.