The gas-phase protonation mechanism of ferrocene is investigated using an
effective potential describing electrostatic, polarization, and short-range
repulsion energy components.R The parameters of the potential are deduced
from a least-squares fit to energy profiles calculated using local-spin
density or Hartree-Fock methods. It is shown that this model, which provides
a clear physical interpretation, leads to a good description of this
reaction mechanism. In addition, a molecular dynamics simulation of 
ferrocene based on an intramolecular force field developed in this work
is presented.