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Title: Electron emission induced by resonant coherent ion-surface interaction at grazing incidence

Abstract

A new spectroscopy based on the resonant coherently induced electron loss to the continuum in ion-surface scattering under grazing incidence is proposed. A series of peaks, corresponding to the energy differences determined by the resonant interaction with the rows of atoms in the surface, is predicted to appear in the energy distribution of electrons emitted from electronic states bound to the probe. Calculations for MeV He{sup +} ions scattered at a W(001) surface along the {l angle}100{r angle} direction with a glancing angle of 0--2 mrad show a total yield close to 1.

Authors:
 [1];  [2];  [3]
  1. (Departamento de Ciencias de la Computacion e Inteligencia Artificial, Facultad de Informatica, Universidad del Pais Vasco, Apartado 649, 20080 San Sebastian (Spain))
  2. (Centro Atomico Bariloche, Comision Nacional de Energia Atomica, 8400 San Carlos de Bariloche, Rio Negro (Argentina))
  3. (Departamento de Fisica de Materiales, Facultad de Quimica, Universidad del Pais Vasco, Apartado 1072, 20080 San Sebastian (Spain))
Publication Date:
OSTI Identifier:
7071003
Alternate Identifier(s):
OSTI ID: 7071003
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; (United States); Journal Volume: 69:16
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; HELIUM IONS; COHERENT SCATTERING; ION COLLISIONS; ELECTRON EMISSION; TUNGSTEN; CATIONS; INCIDENCE ANGLE; ION SPECTROSCOPY; MEV RANGE; RESONANCE; SURFACES; THEORETICAL DATA; CHARGED PARTICLES; COLLISIONS; DATA; ELEMENTS; EMISSION; ENERGY RANGE; INFORMATION; IONS; METALS; NUMERICAL DATA; SCATTERING; SPECTROSCOPY; TRANSITION ELEMENTS 665300* -- Interactions Between Beams & Condensed Matter-- (1992-)

Citation Formats

Garcia de Abajo, F.J., Ponce, V.H., and Echenique, P.M. Electron emission induced by resonant coherent ion-surface interaction at grazing incidence. United States: N. p., 1992. Web. doi:10.1103/PhysRevLett.69.2364.
Garcia de Abajo, F.J., Ponce, V.H., & Echenique, P.M. Electron emission induced by resonant coherent ion-surface interaction at grazing incidence. United States. doi:10.1103/PhysRevLett.69.2364.
Garcia de Abajo, F.J., Ponce, V.H., and Echenique, P.M. Mon . "Electron emission induced by resonant coherent ion-surface interaction at grazing incidence". United States. doi:10.1103/PhysRevLett.69.2364.
@article{osti_7071003,
title = {Electron emission induced by resonant coherent ion-surface interaction at grazing incidence},
author = {Garcia de Abajo, F.J. and Ponce, V.H. and Echenique, P.M.},
abstractNote = {A new spectroscopy based on the resonant coherently induced electron loss to the continuum in ion-surface scattering under grazing incidence is proposed. A series of peaks, corresponding to the energy differences determined by the resonant interaction with the rows of atoms in the surface, is predicted to appear in the energy distribution of electrons emitted from electronic states bound to the probe. Calculations for MeV He{sup +} ions scattered at a W(001) surface along the {l angle}100{r angle} direction with a glancing angle of 0--2 mrad show a total yield close to 1.},
doi = {10.1103/PhysRevLett.69.2364},
journal = {Physical Review Letters; (United States)},
number = ,
volume = 69:16,
place = {United States},
year = {Mon Oct 19 00:00:00 EDT 1992},
month = {Mon Oct 19 00:00:00 EDT 1992}
}
  • The resonant coherent interaction of an ion with an oriented crystal surface, under grazing-incidence conditions with respect to a special direction of the crystal, gives rise to electron loss to the continuum from electronic bound states of the ion. The calculations presented below predict large probabilities for electron emission due to this mechanism. The electrons are emitted with well defined energies, expressed in terms of the condition of resonance. Furthermore, the emission takes place around certain preferential directions, which are determined by both the latter condition and the symmetry of the surface lattice. Our calculations for MeV He[sup +] ionsmore » scattered at a W(001) surface along the [l angle]100[r angle] direction with glancing angle of 0--2 mrad indicate a yield of emission close to 1. Using heavier projectiles, one obtains smaller yields, but still large enough to be measurable in some cases (e.g., [approx]0.9 for 53 MeV B[sup 4+] and an angle of incidence of 1 mrad). Besides, the initial bound state is energy shifted due to the interaction with both the crystal potential and the velocity-dependent image potential. This results in a slight shift of the peaks of emission, which suggests a possible spectroscopy for analyzing the dynamical interaction of electronic bound states with solid surfaces.« less
  • We have measured the energy and angular distributions of electrons emitted in collisions of 40--80-keV protons with a solid surface at grazing incidence. The angular distributions were investigated in the region of the specularly reflected ion beam. A broad peak in the spectrum is observed and tentatively ascribed to electron loss from projectiles neutralized at the surface.
  • Convoy electron spectra have been measured in coincidence with specularly reflected ions in grazing-incidence collisions of carbon ions with a silicon (100) surface. Absolute yields of convoy electrons have been determined experimentally and compared with the results obtained from a classical trajectory Monte Carlo simulation. By comparing the velocity dependence of the convoy yields with theory, we are able to assess the relative contribution to convoy emission from valence and core electron capture to continuum states of the projectile. {copyright} {ital 1998} {ital The American Physical Society}
  • We present a multichannel theory for resonant charge transfer in ion-surface collisions at grazing incidence at intermediate velocities (vapprox. =1 a.u.) taking into account the nonorthogonality of the initial and the final states. Kinematic resonances occur between the atomic projectile levels and the Galilei-shifted conduction band of a metal. The time-dependent Schroedinger equation can be solved in the adiabatic approximation for the slow perpendicular motion (v/sub perpendicular/<<1). As an application we calculate the complete n = 2 density matrix for H(n = 2) following proton scattering at a gold surface at grazing incidence (theta = 5/sup 0/). The shape ofmore » the charge cloud around the receding hydrogen atom is determined.« less
  • In this work, electron emission spectra produced by impact of fast protons on Al(111) surfaces are theoretically and experimentally studied. Contributions coming from the different electronic sources of the metal--atomic inner shells and valence band--are analyzed as a function of the angle of electron emission. In the forward direction, the inner-shell ionization process is the dominant mechanism. The valence emission, instead, becomes important when the ejection angle is separated from the specular-reflection direction. In both angular regions, theoretical and experimental values are in reasonable agreement. The energy shift and broadening of the convoy electron peak at glancing observation angles aremore » well described by the present model, which takes into account the influence of the induced surface field on the ionized electron.« less