Ultrafast Molecular Processes

Knowing the details entails knowing about the very short-lived states molecules pass through on their way to chemical products. Studies of short-lived species require diagnostics that are just as fast as the lifetimes of the states studied. The availability of femtosecond lasers promises to revolutionize our views about chemical reactions. Femtosecond laser pulses have been used by Carl Hayden in the Chemical Dynamics Laboratory to initiate chemical processes and subsequently follow the progress of these processes. Typically a femtosecond laser pulse is used to excite a sample of isolated molecules in a molecular beam. A second femtosecond pulse ionizes the excited molecules. We monitor the velocities and mass spectrum of the ions produced as a function of time delay between the excitation and ionization lasers. Our recent work has focused on the development of a unique new apparatus that greatly expands our capabilities for time-resolved studies using photoionization and photoelectron spectroscopy.