exc-disp . The solid lines display linear fits of data points, and the gray dotted line corresponds to the perfect correlation. (b) Histogram of vdW-OQDO charge (q) computed across the S12L dataset for carbon, hydrogen, nitrogen and oxygen. For every species, the dotted gray line denotes the position of the mean value (displayed in the plot). In the conventional parametrization of MBD, all charges are set to 1 a.u., which is highlighted by the gray dashed line.