Indicated by \(G_{\rm{r}}\) or \(G_{\rm{el}}\) if the repulsion is due to electric effects (\(g_{\rm{r}}\) or \(g_{\rm{el}}\) is taken for unit area of each of two flat and parallel surfaces). \(G_{\rm{r}}\) (or \(G_{\rm{el}}\)) is defined as \[G_{\rm{r}} ({\rm{or\ }} G_{\rm{el}}) = \left[\int \limits_{\rm{final\ distance}}^{\infty} {\rm{Force.d (distance)}}\right]_{T,p}\]