Influence of coadsorbed potassium on the electron-stimulated desorption of F sup + , F sup minus , and F sup * from PF sub 3 on Ru(0001)

Journal Article · Mon Jun 15 04:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.45.14264· OSTI ID:7183099

Joyce, S A; Clark, C ^[1]; Chakarian, V; Shuh, D K; Yarmoff, J A ^[2]; Madey, T E; Nordlander, P; Maschhoff, B; Tao, H ^[3]

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1. National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
2. Department of Physics, University of California, Riverside, California 92521 (United States) Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)
3. Department of Physics and Laboratory for Surface Modification, Rutgers, The State University, Piscataway, New Jersey 08855 (United States)

The electron-stimulated-desorption ion angular distributions (ESDIAD) of positive ions, negative ions, and metastable species from PF{sub 3} and K coadsorbed on a Ru(0001) surface are measured. In the absence of K, only positive- and negative-ion ESDIAD is observed, showing highly anisotropic, off-normal fluorine-ion emission (F{sup +}, F{sup {minus}}) from PF{sub 3}, which demonstrates that PF bonds are inclined away from the surface normal. In the presence of K, ESDIAD patterns of F{sup +}, F{sup {minus}}, and metastable F{sup *} display only normal emission, suggesting a reorientation or chemical reaction which results in fluorine bonding perpendicular to the surface. Thermal desorption spectrometry, Auger electron spectroscopy, and soft-x-ray photoemission (SXPS) are used to determine the surface chemistry as an aid in intepreting the ESDIAD results. The SXPS data show that in the presence of potassium, PF{sub 3} dissociates, possibly forming KF-like species, which suggests that an alkali-metal-induced chemical reaction is reponsible for the changes observed in ESDIAD. The yields of the various desorbed fluorine species vary strongly with potassium coverage; the results for F{sup {minus}} and F{sup *} are interpreted in terms of a charge-transfer model.

• DOE Contract Number: AC02-76CH00016
• OSTI ID: 7183099
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 45:24; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

664300* -- Atomic & Molecular Physics-- Collision Phenomena-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ALKALI METALS
ATOMS
BEAMS
CHEMICAL REACTIONS
CHEMISORPTION
ELECTRON BEAMS
ELEMENTS
EMISSION
ENERGY RANGE
EV RANGE
EV RANGE 100-1000
FLUORIDES
FLUORINE
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HALOGENS
ION EMISSION
LEPTON BEAMS
METALS
NONMETALS
PARTICLE BEAMS
PHOSPHORUS COMPOUNDS
PHOSPHORUS FLUORIDES
POTASSIUM
RUBIDIUM
SEPARATION PROCESSES
SORPTION
SURFACE PROPERTIES