Correction of repulsive potential energy surface for photodissociation of H₂O in the à state

We present in this paper the application of the IPSVD (inverse perturbation via singular value decomposition) method to correct repulsive potential energy surfaces (PES) for half-scattering problems by directly inverting the experimental spectroscopic data. Specifically in the present model study, we start from the ab initio PES of Engel, Schinke, and Staemmler for the excited à state and use the IPSVD method to correct the PES by directly inverting the measured absorption spectrum. The corrected model PES can accurately reproduce the total absorption spectrum in photodissociation of H₂O in the à state within the energy range of our study. Our model study shows great promise for future application of the IPSVD method to correct multidimensional repulsive potential energy surfaces for half- and full-scattering problems.