Electron momentum spectroscopy of atoms, molecules, and thin films

Compton scattering from hydrogen and helium atoms

“…has been calculated with the non-relativistic wave functions entering formula (5) and neglecting the terms of the order ε/m, and F is given by (9). This expression for F and energy-momentum conservation equation (12) are the same as in the case of hydrogen atom with the replacement of the ionization potential of hydrogen atom |ε| by the single ionization potental of helium atom |ε i |.…”

Multiple ionization processes involving fast charged particles

“…Besides those cited above, there are a number of reviews devoted to the specific topic of electron momentum spectroscopy that have been published in the literature. These are book by Weigold and McCar thy [14] and review by Coplan et al [15], in addition to review by Neudachin et al [7] mentioned earlier. However, in most of these works, the case of (e,2e) reactions is considered, with a huge experimental database related to the latter and collected during the 1960s to 1980s.…”

“…In the integrand, only the exponentially oscillating term is kept that contains the small momenta p 3 and q = p s + p e -p 0 . It is the EMS geometry that ensures a small value of the momentum q at large p 0 , p s , and p e : the plane angles θ s and θ e of the momenta p s and p e with respect to p 0 are approxi mately equal to ϯ45°, and E s ~ E e ~ E 0 /2 (for more detail, see [7]).…”

“…If, for definiteness, one talks of multielectron target ionization by fast electrons (with energies of a few keV), then there are the so called dipole (e,3e) reactions, in which an incoming electron transfers a small amount of the momentum and energy to an atom and, therefore, goes out with almost unchanged velocity, and quasi elastic (e,3e) reactions (or electron momentum spectroscopy (EMS)), when there are two fast electrons in the final state with nearly identical energies and angles. The differential cross sections of (e,3e) processes with completely measured angles and energies of all three final electrons are extremely small [5,6], especially in the case of EMS [7]. Therefore, one resorts to the measurements of cross sections of lower multiplicity, say, (e,3-1e), when no slowly moving electron is detected [8].…”

“…Therefore, one resorts to the measurements of cross sections of lower multiplicity, say, (e,3-1e), when no slowly moving electron is detected [8]. Although (e,3e) experiments in quasi elastic kinematics are rare nowadays, they are quite informative in effectively discerning a degree of elec tron pair correlations in the multiparticle wave func tion of a target [7,8].…”