ABSTRACT
This chapter describes the particular electrons in an atom or molecule that respond most strongly to an applied field are determined by the frequency of the field. It discusses time-resolved, X-ray absorption in the biologically relevant system of myoglobin. The chapter explores X-ray transient absorption on a different molecule. It considers two measurements of electronic state couplings in molecules. The first experiment uses time-resolved photoelectron spectroscopy (TRPES) to time resolve changes in electronic state character, while the second uses fluorescence gating to measure nonradiative lifetimes of excited states. The chapter discusses measuring dynamics in one-dimensional systems using TRPES. It considers this idea in detail, introducing a new experimental method for measuring inhomogeneous systems. The chapter looks at photoluminescence measurements in an important model system for solid-state physics: a quantum dot. It discusses multielectron dynamics that occur after removal of an inner-orbital electron from a system.
