AU, AG and NI

These types specify Sutton-Chen potentials of the appropriate form.[37] Three additional real parameters must be specified using the PARAMS keyword in the odata file, namely Sutton and Chen's $\epsilon$, $c$ and $a$, in this order. The nearest neighbour distance in the prevailing unit system is $a/\sqrt{2}$. Hence, using $a=\sqrt{2}$ corresponds to a unit system where the bulk nearest-neighbour distance is 1. Subroutines used: scdiff.