Quantum functional sensitivity analysis within the log-derivative Kohn variational method for reactive scattering

A new approach to calculating quantum functional sensitivity maps of transition probabilities is described in this paper. This approach is based on the log-derivative version of the Kohn variational principle and is applied here to the collinear H+H₂ hydrogen exchange reaction. The sensitivity maps provide detailed quantitative information about how variations in the potential energy surface affect the state-to-state transition probabilities. The key issues investigated are (i) the evolution of sensitivity structure in the 0.30-1.50 eV range of total energy; (ii) the comparison of sensitivity structure on the Porter-Karplus, the Liu-Siegbahn-Truhlar-Horowitz, and the double-many-body-expansion potential energy surfaces; and (iii) the range of linearity for first order sensitivity predictions.