Electronic structure of the alkaline-earth fluorides studied by photoelectron spectroscopy

Determining binding energies of valence-band electrons in insulators and semiconductors via lanthanide spectroscopy

“…[1][2][3][4] Traditionally, photoelectron spectroscopy techniques are used to determine the electron binding energies in the upper band states of compounds. 2,[5][6][7] It requires ultrahigh vacuum and the properties close to the surface are probed. One has to deal with surface effects, sample charging, contact potentials, and limited resolution leading to substantial systematic and random error.…”

Structure and diffusion of intrinsic defects, adsorbed hydrogen, and water molecules at the surface of alkali-earth fluorides calculated using density functional theory

“…2 For alkali-earth surfaces, their interaction with water is particularly relevant due to their historical role in acid production 3,4 and their developing role as dielectric thin films in micro-and optoelectronics. 5,6 The basic fluorite bulk and surface structures have been the subject of numerous experimental and computational studies, [7][8][9][10][11][12][13][14][15][16][17][18][19] and more recent low-energy electron diffraction studies have looked into the surface's structure in detail. 20 Studies of water on the surface have been more sparse, generally predicting that water weakly interacts with the surface in normal conditions, 21 but can dissociate or even etch the surface in the presence of surface defects or at high pH.…”

A new gamma camera for positron emission tomography

“…The fast luminescence emission is expected to be located in the vicinity of hv=E -0.5AE where E is the difference in energy between the tops of vc J v vc the valence-and the core bands and AE is the total width of the v valence band. For these energy differences, values of respectively 7-8 eV and 3-4 eV have been reported [107]. This brings the expected average value for the wavelength of the emission to about 205 nm.…”

“…A study of the energy levels of the alkaline earth fluorides is presented in ref. [107]. Table XV summarizes the experimental values of the energy gaps between the different bands: E is the distance between top of the 2pF vc _ P P valence band and the top of the core band (3pCa , 4pSr , 5pBa ), AE .…”