Structure calculations of polyethylene crystals: A DFT approach
نویسنده
چکیده
Density functional theory (DFT) calculations are performed to find the structural parameters of orthorhombic polyethylene crystal. Computations are carried using Plain wave self-consistent field method implemented in the PWscf software and various pseudo-potentials are used. The calculated values of geometrical parameters are in good agreement with reported values, but the cohesive energy show wide disagreement. This highlight the failure of DFT in modeling polymeric systems which can be attributed to the improper treatment of dispersion or van der Waals (vdW) interactions in the usual DFT framework. A methodology for elastic constant calculations is described.
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