We take advantage of the nonuniqueness of the diabatic basis to make the diabatic and adiabatic potentials the same in asymptotic regions. Therefore, the first 𝑁 !"#"$! elements of 𝚵 % 23 are the asymptotic energies of O + O2 (which are functions of the O2 internuclear distance but independent of the O-to-O2 distance), and the remaining 𝜈 -𝑁 !"#"$! elements are zero. The role of F is to decay 𝐳 % ()' to its asymptotic form, given by 𝚵 % , and therefore, in asymptotic regions, 𝐚 % ()' 𝐑 ! ./ #!67,"".8 9$:.-/ J⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯L 𝚵 % 23 (8) One of the problems with conventional machine-learned PESs is that in regions where there is no data or insufficient data, the model (i.e., the neural network) may predict unphysical results