A systematical computational study of the lattice and rotational dynamics of the methyl halides, which belong to the most simple organic molecules containing CH3 groups, was done. Because of their simplicity there might be a chance to understand and model the dynamics of these systems by combining nonbonded pair interactions and crystallographic information. Based on the experimentally determined crystal structure, which was not relaxed during the calculations, interactions were modeled using the transferable parameters of the universal force fields. The lattice dynamical calculation can reproduce with reasonable accuracy the low-energy regime of the lattice excitations as well as the single-particle rotational potential of the CH3 group of the respective halide. (C) 2004 American Institute of Physics.