(4) To improve upon some shortcomings of the vdW-DF1 approach, especially overestimated equilibrium distances and exaggerated attractive dispersion interactions, a modified version of the non-local kernel was implemented by Lee et al. in their vdW-DF2 method. A further improved version of vdW-DF2, which uses a revised B86b exchange functional instead of PW86 exchange, was later proposed by Hamada (rev-vdW-DF2). Table : Overview of dispersion-corrected DFT approaches used in this work.