On the use of the BLYP functional for the DFT calculation of graphite–hydrogen systems

This letter focuses on a possible pitfall that can occur in the DFT calculation of graphite–hydrogen interactions under tokamaks conditions. Calculations based on the BLYP functional, in fact, result in a stable –C2H3 group that other functionals (OLYP, XLYP, PBE and BP) do not confirm.