Potential energy surfaces numerical convergence

In any given region of the Born-Oppenheimer potential-energy surface, we can judge which structure of (5.6a)-(5.6d) is best by determining which perturbative decomposition in (5.7) is numerically most rapidly convergent. 

There is also a CS calculation for the reactions H + H2(v = 1) e- H2(v ) + H V = 0,1 on the Porter-Karplus potential energy surface,[39]. However, due to numerical problems, no fully converged results were obtained. Again, this lack of convergence may affect the absolute values but is expected to yield more reliable values for branching ratios. Here we find that the classical 1(1,0) values are 2 whereas both the CS and RIOSA yield values of 4. 

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