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The photoelectric effect rapidly decreases in significance in the gamma-ray region of the spectrum, with increasing photon energy. It is also more likely from elements with high atomic number. Consequently, high- Z materials make good gamma-ray shields, which is the principal reason why lead ( Z = 82) is preferred and most widely used.
When either the laser intensity is further increased or a longer wavelength is applied as compared with the regime in which multi-photon ionization takes place, a quasi-stationary approach can be used and results in the distortion of the atomic potential in such a way that only a relatively low and narrow barrier between a bound state and the continuum states remains.
The electrons released from the target will have approximately an integer number of photon-energies more kinetic energy. In intensity regions between 10 14 W/cm 2 and 10 18 W/cm 2, each of MPI, ATI, and barrier suppression ionization can occur simultaneously, each contributing to the overall ionization of the atoms involved. [11]
The photoelectric effect dominates at low energy, but above 5 MeV, pair production starts to dominate. Even though photons are electrically neutral, they can ionize atoms indirectly through the photoelectric effect and the Compton effect. Either of those interactions will cause the ejection of an electron from an atom at relativistic speeds ...
The physics behind the PES technique is an application of the photoelectric effect. The sample is exposed to a beam of UV or XUV light inducing photoelectric ionization. The energies of the emitted photoelectrons are characteristic of their original electronic states, and depend also on vibrational state and rotational level.
Upon ejection, the kinetic energy of the Auger electron corresponds to the difference between the energy of the initial electronic transition into the vacancy and the ionization energy for the electron shell from which the Auger electron was ejected. These energy levels depend on the type of atom and the chemical environment in which the atom ...
Gaseous ionization detectors are used in experimental particle physics to detect photons and particles with sufficient energy to ionize gas atoms or molecules. Electrons and ions generated by ionization cause a current flow which can be measured.
If Albert Einstein's photoelectric law is applied to a free molecule, the kinetic energy of an emitted photoelectron is given by =, where h is the Planck constant, ν is the frequency of the ionizing light, and I is an ionization energy for the formation of a singly charged ion in either the ground state or an excited state.