Fermi momentum above metal surface from electrons ejected by impact of He atoms

Winter, H.; Lederer, S.; Winter, H.

doi:10.1209/epl/i2006-10192-7

Cited by 9 publications

(2 citation statements)

References 24 publications

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“…This corresponds to 1.5-3 × 10 7 cm s −1 (117-470 eV amu −1 ) for most metals, consistent with extrapolation of the experimental results for light projectiles [12]. Deviations from (2.1) contain information on the velocity distribution of electrons at the surface [13].…”

Section: Excitation Mechanismssupporting

confidence: 83%

Electron Emission from Surfaces Induced by Slow Ions and Atoms

Baragiola

Riccardi

2008

Springer Series in Materials Science

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Electron emission from surfaces is of crucial importance in determining the properties of electrical discharges, where it is caused by the impact of ions, atoms, electrons, and photons. At the microscopic level, the physics of electron emission from solid targets is usually described by a three-step model: electron excitation, electron transport to the surface, and its escape through the surface. This division serves a heuristic purpose and it must be borne in mind that, in purely surface events, actually only one step is involved. What distinguishes electron emission by different incoming particles is the excitation step [1], which depends strongly on the momentum of the particle. This is because there is a minimum energy needed to extract an electron from the solid (work function for metals, band gap plus electron affinity for nonmetals) and this energy transfer implies a momentum transfer from the projectile.This chapter is concerned with heavy particle collisions (ions and atoms) at low energies (below a few keV) and will discuss first the physical mechanisms and then applications to electrical discharges in gases. The overall picture of electron emission induced by heavy particles is the following. Electrons are excited from the target or the projectile as a result of Coulomb interactions involving the nuclei and electrons through mechanisms that are grouped in two categories, potential and kinetic, depending on the source of the excitation energy. Such excitations occur mostly in binary collisions at the surface or very shallow depths, since the penetration depth of low-energy atomic projectiles is usually very shallow, tens of nm or less. The excited electrons can be ejected directly into vacuum or undergo a series of collisions in the target solid (electron transport) on their way to the surface. The collisions are either elastic scattering with atomic cores, which cause large deflections in trajectories, or energy loss collisions by scattering with other electrons, contingent on the availability of electronic states. As a result of such inelastic scattering, the electrons which succeed in escaping the solid come from a shallow depth, of the order of 2 nm for metals and semiconductors and up to a few tens of

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Section: Excitation Mechanismssupporting

confidence: 83%

Electron Emission from Surfaces Induced by Slow Ions and Atoms

Baragiola

Riccardi

2008

Springer Series in Materials Science

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“…Electron emission processes are grouped in the two main categories of Potential Electron Emission (PEE) and Kinetic electron emission (KEE). PEE occurs at the expense of the potential energy carried by incoming ions [17][18][19], while KEE occurs from the conversion of the kinetic energy of incoming projectiles [19][20][21][22][23][24]. Studies of PEE dates back to the 50s, starting with the pioneering work of Hagstrum [17,[25][26][27][28], who discussed PEE in terms of the conversion of the potential energy carried by incoming projectiles into electronic excitation and emission through Auger transitions.…”

Section: Introductionmentioning

confidence: 99%

Plasmon Excitation in the Interaction of Slow Singly Charged Argon Ions with Magnesium

Riccardi

2024

Solids

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We report angle-resolved energy spectra of electron emitted in the interaction of slow singly charged heavy ions with Mg surface. The work is focused mainly on the excitation of plasmons of Mg under Argon impact. Potential excitation of plasmons occurs when incoming ions are neutralized at the expense of the potential energy carried by incoming ions. The process competes with the known mechanisms of neutralization via Auger transitions. Differently from Al samples, our results show that the neutralization of Ar+ ions at Mg is dominated by the excitation of surface plasmons by the potential energy released in the electron capture process that neutralizes incoming ions. Bulk plasmon excitation is observed at higher impact energy and is ascribed to fast electrons excited by the transfer of the kinetic energy of incoming particles. The data show that bulk plasmon excitation occur inside the bulk, while the theoretically predicted excitation by potential energy transfer of incoming projectiles is not observed.

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Kinetic Electron Emission for Grazing Scattering of Atoms and Ions from Surfaces

Winter¹

Springer Tracts in Modern Physics

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Fermi momentum above metal surface from electrons ejected by impact of He atoms

Cited by 9 publications

References 24 publications

Electron Emission from Surfaces Induced by Slow Ions and Atoms

Electron Emission from Surfaces Induced by Slow Ions and Atoms

Plasmon Excitation in the Interaction of Slow Singly Charged Argon Ions with Magnesium

Kinetic Electron Emission for Grazing Scattering of Atoms and Ions from Surfaces

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