Nucleophilic Parr function	$P{}^{-}\left(\mathbf{r}\right)={\rho }_s^{rc}\left(\mathbf{r}\right)$
Electrophilic Parr function	$P{}^{+}\left(\mathbf{r}\right)={\rho }_s^{ra}\left(\mathbf{r}\right)$