Conceptual Insights into the Interaction of the Phase of the Electric Field and Molecular Spectroscopy to Further Understand Molecular Isomerization and Solute-Solvent Interactions

The real and imaginary parts of the susceptibility are fundamentally associated with the molecular dispersion and absorption, respectively. Measurement of the molecular dispersion has given insight into underlying molecular dynamics such as the identification of conical intersections and solute-solvent interactions. We show that when using a shaped pulse(s), it is possible to mix the real and imaginary parts of the nonlinear susceptibility into the molecular absorption. We then explain how to separate the real and imaginary parts of the nonlinear susceptibility when using a shaped pulse(s). We describe how the imaginary (absorption-like) and real (dispersion-like) parts of the nonlinear susceptibility can be used to understand molecular dynamics involving conical intersections in solvated molecules. We calculate the inhomogenous lineshape for a solvated molecule and show that when the phase is resonant with a vibrational line that the lineshape changes from absorption-like to dispersion-like. We find that the linear polarization is sensitive to the phase of the pulse.