ABSTRACT
This chapter provides a single molecular system using multiple experimental approaches, and supporting calculations. It shows how different techniques provide different views, which can ultimately be combined to build a complete picture of the dynamics. The chapter considers the system that is cyclohexadiene (CHD). Excitation of CHD by a ultraviolet (UV) pump pulse at 266 nm initiates wave packet dynamics on the excited 1B-state. The chapter begins with gas-phase, electron diffraction experiments, where a UV pump pulse initiates the ring-opening reaction and is followed by a time-delayed probe consisting of a pulse of 30-kV electrons. In diffractive measurements, one compares radial distribution functions at different time delays with measured or calculated distributions for relevant molecular geometries such as reactant or product. In contrast to spectroscopic measurements, ultrafast electron diffraction and X-ray diffraction provide information that is more directly related to molecular structure.
