INVERSION OF ULTRAFAST BUMP-PROBE SPECTROSCOPIC DATA

Spectroscopic observables are governed by the dynamics on the ground a nd excited potential energy surfaces. An inversion scheme is presented to iteratively construct the potential surface which reproduces exper imental data. Special attention is drawn to the nonlinear character of the inversion problem and, in particular, to the role of ultrafast pu mp-probe spectroscopy for dealing with it. The regions of inversion, i .e., the nuclear configurations for which the potential is to be deter mined, are identified by calculating the observable-potential sensitiv ity function. A method is introduced for calculating these sensitivity functions in a numerically converged time-dependent quantum mechanica l fashion. These functions are the basic building blocks of the invert ed potential. Two demonstrations of the procedure are presented, both use simulated pump-probe spectroscopic data. The first, applied to the ICN molecule, reconstructs the medium- and long-range parts of the di ssociative excited surface. The second attempts to reconstruct the bou nd excited potential surface of NCO.