[en] We study the dynamical properties of the Mermin model, a simple quantum dissipative model with a monochromatic environment, using analytical and numerical methods. Our numerical results show that the model exhibits a second order phase transition to a localized state before which the system is effectively decoupled from the environment. In contrast to the spin-boson model, the Mermin model exhibits an ''orthogonality catastrophe,'' defining the critical point, before dissipation has destroyed all coherent behavior. An analytic approach based on the Liouvillian technique, although successful in describing the phase diagram of spin-boson and related models, fails to capture this essential feature of the Mermin model