<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Ne</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">*</mml:mi><mml:mi mathvariant="normal">*</mml:mi></mml:mrow></mml:msup></mml:mrow></mml:math>autoionizing states and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Ne</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:m

Grizzi, O.; Shi, M.; Bu, H.; Jw, Rabalais; Ra, Baragiola

doi:10.1103/physrevb.41.4789

Cited by 71 publications

(8 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This process has recently been observed for a number of different systems. 5,[10][11][12][13] Another possibility is that the collision introduces positive ions into the initial mix of states that gets propagated out from the surface and that some fraction of these survive.…”

Section: Positive-ion Formationmentioning

confidence: 99%

“…While there are both fundamental and practical reasons to improve our understanding of these systems, developing this understanding is an experimental and theoretical challenge due to the large number of effects that must be considered. The effects we consider are the resonant 6 and Auger 7-9 charge-exchange mechanisms, electron promotion in hard collisions, [10][11][12][13][14] relaxation of the scattered excited states through Auger autoionization, 10,11,13 coupling to collision dynamics, 15 and the velocity of the scattering atom relative to the surface electrons. 16,17 Furthermore, the intrinsic multichannel character of the problem due to the degenerate p orbital electrons 18 has to be considered.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Positive- and negative-ion formation in low-energyO+-Cu(001) scattering

1998

View full text Add to dashboard Cite

For incident 0.4-7-keV O ϩ beams scattered from Cu͑001͒, we have measured energy and angular distributions of O ϩ and O Ϫ ions in the scattered flux, and performed accurate quantitative measurements of the O ϩ /O Ϫ ratios. The O ϩ /O Ϫ ratios depend on the scattering geometry and, for a given geometry, decrease with decreasing scattered perpendicular velocity. The qualitative differences between the energy and angular spectra for the scattered positive and negative ions indicate that this trend is due to the rapid decrease of the O ϩ fraction. These data and general arguments based on the energies of the states of the O-Cu system are used to identify key mechanisms responsible for the presence of O ϩ and O Ϫ in the scattered flux. We conclude that the resonant and Auger charge transfer mechanisms are both important. Furthermore, the data indicate that the O ϩ ions are generated in the hard collision between the incident atom and a surface atom. These collisions explain the geometry dependence of the measured O ϩ /O Ϫ ratios. ͓S0163-1829͑98͒00640-7͔

show abstract

Section: Positive-ion Formationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Positive- and negative-ion formation in low-energyO+-Cu(001) scattering

1998

View full text Add to dashboard Cite

show abstract

“…37 for a review͒. In particular, inelastic losses, high ion yields ͑Ͼ50% Ne + off Mg͒, [43][44][45] and multiply-charged scattered projectiles ͑Ne ++ and Ne 3+ off Mg, Al, and Si͒ 40,46-50 have been seen for single binary collisions involving Ne + projectiles at keV impact energies. Such "richness" in the scattering behavior is intimately linked to local charge exchange phenomena which occur as the atomic orbital ͑AO͒ states of the collision partners quantum mechanically mix into hybrid molecular orbitals ͑MOs͒ during the hard collision step ͑the Fano-Lichten MO mechanism͒.…”

Section: B Charge Exchange Involving Ne + With Light Targetsmentioning

confidence: 98%

Low-energy ion beamline scattering apparatus for surface science investigations

Gordon

Giapis

2005

Review of Scientific Instruments

View full text Add to dashboard Cite

We report on the design, construction, and performance of a high current ͑monolayers/ s͒, mass-filtered ion beamline system for surface scattering studies using inert and reactive species at collision energies below 1500 eV. The system combines a high-density inductively coupled plasma ion source, high-voltage floating beam transport line with magnet mass-filter and neutral stripping, decelerator, and broad based detection capabilities ͑ions and neutrals in both mass and energy͒ for products leaving the target surface. The entire system was designed from the ground up to be a robust platform to study ion-surface interactions from a more global perspective, i.e., high fluxes ͑Ͼ100 A/cm 2 ͒ of a single ion species at low, tunable energy ͑50-1400± 5 eV full width half maximum͒ can be delivered to a grounded target under ultrahigh vacuum conditions. The high current at low energy problem is solved using an accel-decel transport scheme where ions are created at the desired collision energy in the plasma source, extracted and accelerated to high transport energy ͑20 keV to fight space charge repulsion͒, and then decelerated back down to their original creation potential right before impacting the grounded target. Scattered species and those originating from the surface are directly analyzed in energy and mass using a triply pumped, hybrid detector composed of an electron impact ionizer, hemispherical electrostatic sector, and rf/dc quadrupole in series. With such a system, the collision kinematics, charge exchange, and chemistry occurring on the target surface can be separated by fully analyzing the scattered product flux. Key design aspects of the plasma source, beamline, and detection system are emphasized here to highlight how to work around physical limitations associated with high beam flux at low energy, pumping requirements, beam focusing, and scattered product analysis. Operational details of the beamline are discussed from the perspective of available beam current, mass resolution, projectile energy spread, and energy tunability. As well, performance of the overall system is demonstrated through three proof-of-concept examples: ͑1͒ elastic binary collisions at low energy, ͑2͒ core-level charge exchange reactions involving 20 Ne + with Mg/ Al/ Si/ P targets, and ͑3͒ reactive scattering of CF 2 + /CF 3 + off Si. These studies clearly demonstrate why low, tunable incident energy, as well as mass and energy filtering of products leaving the target surface is advantageous and often essential for studies of inelastic energy losses, hard-collision charge exchange, and chemical reactions that occur during ion-surface scattering.

show abstract

“…4 For larger grazing angles of incidence and heavier noble gas atoms, electron promotion in binary collisions of atomic projectiles with target atoms was identified as relevant electron emission mechanism. [5][6][7][8][9] .…”

mentioning

confidence: 99%