Quantum dynamics of photoionization from Cl-2(-) is investigated by constructing a purely one-electron model Hamiltonian of the anion calibrated with the help of ab initio theoretical calculations at the MRSD-CI level. A mean-field time-dependent Fourier grid Hamiltonian method is used to investigate the modulation of the dynamics of photoionization from Cl-2(-) caused by the coupling of electronic and nuclear motions. Vibrational quenching at low coupling strength is predicted to turn into vibrational enhancement of ionization at higher strengths of coupling. (C) 2004 Elsevier B.V. All rights reserved.