The Spin-Boson Hamiltonian (SBH) is a two-level system linearly coupled to a bath of uncoupled harmonic oscillators. Such a simple description of the environment and its coupling to the reaction coordinate can effectively simulate a variety of physical processes by properly tuning a few parameters of the model. In this work, we mimic a slowly decaying nonadiabatic phenomenon in the weak coupling limit. We constructed the SBH model with 10 harmonic bath modes, each with 1 amu mass.