Contribution of van der Waals interactions to the adsorption energy of C2H2, C2H4, and C6H6 on Si(100)

► van der Waals interactions of acetylene, ethylene, and benzene with Si(100). ► van der Waals energy-corrected DFT scheme with self-consistent screening effects. ► Increase of van der Waals energy with respect to the size of molecules.