Contracted basis functions for variational solutions of quantum mechanical reactive scattering problems

A new method for constructing efficient basis functions for ℒ² variational calculations of quantum mechanical rearrangements is presented and tested. With this method, using the same contracted basis functions for all channels in a given vibrational manifold, we can obtain reactive transition probabilities for F + H₂ → H + HF(v′). where v′ is the final vibrational state, that are accurate to 0.01 absolute accuracy or 5% relative accuracy with 40% less basis functions than are required for the same accuracy using primitive basis sets and with 60% less basis functions than were used for our previous calculations that were converged to 1%.