I am working on cyclodextrin inclusion complexes and find out their geometries,particularly the orientation of the guest in the cavity. Which computational method out of DFT, MM and MD would provide more accurtate structure?
DFT calculation provides more accurate result but this calculation is applicable for small system and based quantum method. On the other hand, MD and MM calculations are more significant for big systems and based on classical mechanics.
Quantum Mechanics methods are more accurate than Classical Mechanics methods, however the description of your interest is typically from works involving statistical Thermodynamics. So in my opinion, Molecular Dynamics or stochastic simulation (Monte Carlo) are more appropriate for your interest.
For your work on Cyclodextrin inclusion complexes to find the structural geometries, DFT calculation provides more accurate result but you will be able to use the long range correction functionals of DFT (like CAM-B3LYP, M06-2X, wB97-XD), to appreciate the geometries of your complexes at the electronic correlation state.