Richard Tuckett
University of Birmingham, UK
Title: Threshold photoelectron and electron-ion coincidence spectroscopies: past, present and future
Biography
Biography: Richard Tuckett
Abstract
The history and evolution of molecular threshold photoelectron spectroscopy and threshold photoelectron photoion coincidence spectroscopy (TPEPICO) in the gas phase over the last fifty years will be reviewed. Emphasis will be placed on instrumentation and the extraction of dynamical information about energy selected ion dissociation, not on the detailed spectroscopy of certain molecules. Three important advances have greatly expanded the power of the technique, and permitted its implementation in modern synchrotron radiation beamlines. (a) The use of velocity focusing of threshold electrons onto an imaging detector in the 1990s simultaneously improved the sensitivity and electron energy resolution, and also facilitated the subtraction of hot electron background in both threshold electron spectroscopy and TPEPICO studies. (b) The development of multi-start multi-stop collection detectors for both electrons and ions in the 2000s permitted the use of the full intensity of modern synchrotron radiation thereby greatly improving the signal-to-noise ratio. (c) Finally, recent developments involving imaging electrons in a range of energies as well as ions onto separate position-sensitive detectors has further improved the collection sensitivity, so that low density samples found in a variety of studies can be investigated. As a result, photoelectron photoion coincidence spectroscopy is now well positioned to address a range of challenging problems that include the quantitative determination of compositions of isomer mixtures, the detection and spectroscopy of free radicals produced in pyrolysis or discharge sources as well as in combustion studies.