where 𝑁 !"#"$! is the number of electronic states considered. In current work, 𝑁 !"#"$! is 14. The first 𝑁 !"#"$! elements of 𝚵 ! "# are (up to a re-ordering of states and aside from an additive constant) the sum of the three adiabatic diatomic potentials as explained below. The remaining elements of 𝚵 ! "# are zero.