Experimental study of molecular and cluster effects in secondary electron emission

Journal Article · Wed Feb 28 23:00:00 EST 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.41.3959· OSTI ID:6847317

Rothard, H; Kroneberger, K; Veje, E; Clouvas, A; Kemmler, J; Koschar, P; Keller, N; Lencinas, S; Lorenzen, P; Heil, O; Hofmann, D; Groeneveld, K ^[1]

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1. Institut fuer Kernphysik, Johann-Wolfgang-Goethe-Universitaet, August-Euler-Strasse 6, D-6000 Frankfurt am Main 90, West Germany (DE)

We have measured the ion-induced secondary-electron-emission (SEE) yields in forward and backward directions from thin sputter-cleaned foils in ultrahigh vacuum. C, Al, Ti, Ni, and Cu have been bombarded with H{sup +}, H{sub 2}{sup +}, and H{sub 3}{sup +} (0.3--1.2 MeV/amu), and C and Al have been bombarded with C{sup +}, O{sup +}, and CO{sup +} (15--85 keV/amu). The yields induced by molecular and cluster ions are compared to those induced by the corresponding isotachic monoatomic projectiles. We observe molecular effects as yield reductions at low projectile velocities ({ital v}{sub {ital p}}{approx}{ital v{ital o}}) and yield enhancements at higher velocities ({ital v}{sub {ital p}}{much gt}{ital v{ital o}}). The results are discussed in the framework of the extended kinetic-emission model by Sternglass and the energy-loss model for clusters by Brandt and Ritchie. The velocity dependence of the molecular effect in SEE follows the velocity dependence of the molecular effect in Brandt's energy-loss calculations. Thus it seems that the energy loss is also proportional to SE yields for molecular projectiles at velocities around and above the Bohr velocity {ital v}{sub 0}.

• OSTI ID: 6847317
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 41:7; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

656003* -- Condensed Matter Physics-- Interactions between Beams & Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM
CARBON
CARBON IONS
CHARGED PARTICLES
COLLISIONS
COPPER
ELECTRON EMISSION
ELEMENTS
EMISSION
FOILS
HYDROGEN IONS
ION COLLISIONS
IONS
MATHEMATICAL MODELS
METALS
NICKEL
NONMETALS
OXYGEN IONS
SECONDARY EMISSION
TITANIUM
TRANSITION ELEMENTS
ULTRAHIGH VACUUM