Energy transfer in collisions of benzene molecular ions with a fluorinated self-assembled monolayer surface at normal incidence was studied over the range of collision energies from 0 to 75 eV in a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS). Rice-Ramsperger-Kassel-Marcus (RRKM) theory was used to calculate breakdown graphs for a simplified decomposition scheme of benzene on the time scale of ICR MS detection. Statistical partitioning of excess internal energy between the neutral and the ionic products was included in the theoretical model. Internal energy distributions of the predissociating parent ions were iteratively calculated using the recursive internal energy distribution search (RIEDS) method for each collision energy. On the basis of the above measurements, the collision-energy-dependent E-SID --> E-int energy conversion efficiency was found to maximize at about 19.5% under the conditions of 31 eV SID collision energy.