DFT (Density Functional Theory) is a method used in computational chemistry to calculate the electronic structure of molecules, while Van der Waals interactions refer to weak forces between atoms or molecules that are not covalently bonded.
DFT calculations can include the effects of Van der Waals interactions by using methods such as dispersion corrections or incorporating Van der Waals density functionals into the calculations.
While DFT can provide a good estimation of Van der Waals interactions, it is not always accurate and can be improved by using more advanced methods such as post-Hartree-Fock calculations.
Yes, DFT calculations are limited by the size of the system being studied and the level of theory used. DFT is also not accurate for systems with significant dispersion or non-local electron correlation effects.
It depends on the specific system and the level of accuracy needed. DFT is more computationally expensive but can provide more accurate results, while molecular mechanics is faster but less accurate. Both methods have their own advantages and limitations and can be used in combination for a more comprehensive study of Van der Waals interactions.