Abstract
Electrons can be ejected from a medium after it absorbs one or more photons that have sufficient energy. Electron emission from gas-phase species, which is called photoionization (PI), occurs when the energy of the photon(s) exceeds the ionization potential. The analogous ejection of electrons from surfaces, called photoemission (PE), occurs when the photon energy exceeds the work function. With careful choice of wavelength, a single type of atom, molecule, or ion can be selectively identified by using photoionization, even for very small concentrations. Similarly, the nature of a film surface or adsorbates on this surface can be analyzed with photoemission. For both photoionization and photoemission, the electron flux can be measured as a function of laser wavelength (near the work function or resonances) by tuning the wavelength, or the energy distribution of the emitted electrons can be resolved for a given wavelength. The maximum pressure in the chamber is limited (<1 mTorr) for PI and PE because of electron collection.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
