The aim of this project is to complete our previous experiment on felodipine. This compound possesses four methyl groups. Our QENS and 1H NMR experiments have revealed that two of those groups have a low activation energy (~5 kJ/mol), and NMR indicate that the other two CH3 have a much higher (~14 kJ/mol), but equivalent, activation energy. On the other hand, our calculations (DFT and molecular dynamics simulations), show that half of the methyl groups reorient easily (in agreement with the experiment), but that the other two groups exhibit a different behaviour. One of them has a very large activation energy (~25 kJ/mol from DFT) and appears immobile in the MD simulation, while the other has a lower barrier (~ 15 kJ/mol) and moves in the ns time scale. As the QENS experiment was done only on a TOF spectrometer, the neutron data do not allow us to resolve this apparent contradiction between NMR and simulation. Therefore in order to clarify the disagreement between experimental and theoretical predictions and conclude our study on felodipine we ask for 2 days of beamtime in the backscattering spectrometer IN16B.