Long wavelength acoustic phonons are normally weakly coupled to other vibrational
modes in a crystalline system. This is particularly problematic in molecular dynamics
calculations where vibrations at the system-size scale are typically excited at initiation. The
equilibration time for these vibrations depends on the strength of coupling to other modes, so is
typically very long. A very simple deterministic method is presented which removes this
problem. Examples of equilibration in lithium and a martensitic phase transition in sodium are
used to demonstrate the method.