[en] Atoms ; Carrier concentration ; Electron density measurement ; Electronic structure ; Electrons ; Van der Waals forces ; Atom in a molecules ; Bonding environments ; Correction methods ; Damping functions ; Density-functional theory calculations ; Electron densities ; Electronic structure calculations ; Exchange-correlation functional ; Experimental values ; Free atoms ; Ground-state electrons ; Mean absolute errors ; Mean fields ; Parameter-free methods ; Reference datum ; Van der waals interactions ; Van der Waals radius ; Density functional theory