In MD simulation we have chose potentials from given lists. and by DFT calculation one can calculate ground state energy of molecules or crystal structures. What are the differences or similarities between DFT ground state energy and potential energy of molecular dynamics simulation MD? can we use ground state energy as potential for MD simulations? if not what are the corrections required there?
DFT is a quantum method of calculating energy as well as other properties. On the other hand, you can use empirical potentials to simulate the potential energy and calculate the energy. You can use both empirical potentials or DFT to minimize the energy of a system as well as doing MD.
Empiral potencials (force-fields) are much faster but less accurate than an "ab-initio" method like DFT.
Mr. Das,
If you are trying to compare the energy levels, I suggest to do so as relative potential energies to two different reference points for DFT and MD. I found setting a reference point is crucial, particularly for MD.
DFT calculations use different reference state for the energies ( separate nucleus,electrons ) while potential energy with classical MD simulation only includes the intra and intermolecular potential energies and not the piece due to internal part of the molecular partition function. In the force field development process for MD simulation, people usually scan potential energy surface ( PES ) using DFT and map it to the corresponding classical MD potential energy surface of the molecules. The important point is that the mapping must be done on the relative potential energies ( with respect to minimum of the PES) in DFT and MD simulations.
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