Multiple time scale simulation of a flexible model of CO₂

The reference system propagator algorithm of Tuckerman et al. is applied to a simple model of fexible CO2. The forces are broken up according to three different time scales corresponding to the internal motion, short-range impulsive collisions, and long-range interactions, and three time steps are introduced to integrate the equations of motion. The use of this scheme allows a factor of 8 to 12 to be saved in CPU time over standard integration schemes. © 1994 American Institute of Physics.