| Nonlinear wave packet interferometry (WPI) uses two phase-locked pulse-pairs to excite a molecular electronic population and measures those contributions arising from a one-pulse nuclear wave packet overlapping with a three-pulse nuclear wave packet. The interferogram quantifies the wave-packet interference at the probability-amplitude level and, with knowledge of the three-pulse (reference) wave packets, enables reconstruction of the one-pulse (target) wave packet.; In one-color nonlinear WPI, both pulse-pairs resonate with the same electronic transition and the interferogram measures a sum of wave-packet overlaps. Experimental conditions often minimize mixing of these overlaps and hence permit molecular state reconstruction, as demonstrated by numerical calculations for model harmonic and photodissociative systems. Yet, a one-color reconstruction technique requires information about the Hamiltonian under which the target and reference states propagate. The latter knowledge obviates the practical need for experimental state determination, since computational methods are then a viable, alternative solution.; Two-color nonlinear WPI, in which the pulse-pairs drive different electronic transitions, circumvents the need for information about the target-state Hamiltonian by using an auxiliary electronic level for preparing the reference states. Furthermore, in a two-color experiment, the interferogram measures a single wave-packet overlap, definitely identifying the information necessary for molecular state reconstruction. These features suggest two-color nonlinear WPI could serve as a diagnostic tool for identifying optically-controlled, yet unknown, molecular dynamics. Simulations for model systems and the lithium dimer demonstrate that target states can be reconstructed in the presence of signal noise, thermal mixtures, and rovibrational coupling and in the absence of information about the target-state Hamiltonian.; In the presence of electronic-energy transfer, the interferogram reveals changes in the probability amplitude first-order in the inter-chromophore scalar coupling J. Controlling the polarization of the pulse-pairs enables selective excitation of the components in a model dimer complex and isolation of the overlap between a three-pulse reference wave packet, independent of J, and a one-pulse target wave packet, whose electronic and nuclear degrees of freedom are entangled. The processes underlying coherent energy transfer are identified by interpreting the interferogram with the help of quasi-classical phase-space diagrams.; This dissertation includes both my previously published and my co-authored materials. |
