Time-of-Flight Photoelectron Spectroscopy of Atoms and Molecules

Document Type



Following the advent of third-generation synchrotron-radiation sources with ultra-high brightness and X-ray pulse widths of a few picoseconds, the technique of time-of-flight (TOF) electron spectroscopy has experienced a dramatic enhancement in energy resolution. Using soft-X-ray beams focused to 100 μm or less, a new gas-phase TOF-photoelectron apparatus in operation at the Advanced Light Source (ALS) has demonstrated electron energy resolution as high as 8000 (EE), comparable to some of the best electrostatic analyzers, while maintaining the traditional efficiency of the TOF technique. This apparatus is being used to probe limitations of basic approximations in X-ray photoemission: (1) the independent-particle approximation, and (2) the dipole approximation. In both cases, new limits of these approximations have been discovered in unexpected photon-energy regimes. This paper includes an overview of the TOF technique as well as a summary of results from the ALS on limits of these basic approximations.


Atomic, Molecular and Optical Physics | Physical Chemistry


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