Electron emitted, kinetic energy

TRPES has been recently reviewed and details of the experimental method and its interpretation can be found elsewhere [5], Trans-azobenzene was introduced via a helium supersonic molecular beam into the interaction region of a magnetic bottle photoelectron spectrometer. The molecules were photoexcited by a tunable femtosecond laser pulse (pump pulse) with a wavelength of 280-350nm. After a variable time delay, the excited molecules were ionized by a second femtosecond laser pulse (probe pulse) with a wavelength of 200 or 207nm. The emitted photoelectrons were collected as a function of pump-probe time delay and electron kinetic energy. 

One of the main validations of the nanoplasma model was a measurement of electron kinetic energy distributions by Shao et al [7]. They observed a bimodal distribution, with warm electrons emitted along the polarisation axis, and hot electrons with an isotropic distribution. The nanoplasma model predicted a bimodal distribution, with hot electrons being produced at the resonance, and warm ones created at the beginning of the interaction. 

When internal conversion occurs, there is a probability than an electron from the K shell, L shell, or another shell, may be emitted. The corresponding equations for the electron kinetic energies are... 

The XPS spectrum is a plot of the number of emitted electrons per energy interval vs. their kinetic energy. The work function of the spectrometer can be measured and is constant for a given instrument, allowing the binding energies of the electrons to be determined. 

Photoelectron spectroscopy provides a direct measure of the filled density of states of a solid. The kinetic energy distribution of the electrons that are emitted via the photoelectric effect when a sample is exposed to a monocluomatic ultraviolet (UV) or x-ray beam yields a photoelectron spectrum. Photoelectron spectroscopy not only provides the atomic composition, but also infonnation conceming the chemical enviromnent of the atoms in the near-surface region. Thus, it is probably the most popular and usefiil surface analysis teclmique. There are a number of fonus of photoelectron spectroscopy in conuuon use. 

Aiiger peaks also appear in XPS spectra. In this case, the x-ray ionized atom relaxes by emitting an electron with a specific kinetic energy E. One should bear in mind that in XPS the intensity is plotted against the bindmg energy, so one uses ( Bl.25.1) to convert to kinetic energy. 

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