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| Abstract or Summary |
- A new experimental technique for the study of
atom-surface interactions is obtained by passing an atomic
beam containing high-Rydberg states through a fine mesh
target. The technique is demonstrated to be a sensitive
probe of the electric fields of adsorbed dipole layers in
transmission experiments in which a time-dependent beam
reduction is attributable to field-ionization of the
high-Rydberg atoms.
A thermal-energy Li beam, excited by electron
impact to states with principal quantum numbers near
n = 35, is passed through a 2.1-μm-thick gold mesh with
6.45-μm square holes. The fraction of excited atoms
surviving passage through the target shows a decrease to a
minimum as a function of time, followed by a rise to a final constant value. The rate of these changes is
unaffected by changes in the Li flux, is decreased by an
increase of the mesh temperature, and seems to be increased
with a higher residual gas pressure.
A model of the time dependence of the transmission
based on field-ionization of the high-Rydberg atoms in the
presence of dipole layers of adsorbed H₂O and LiOH (formed in the reaction of H₂O and Li) agrees with the experimental
observations. A calculation of the rate of diffusion of Li
into Au shows that diffusion proceeds too rapidly to allow
observation of effects due to adsorbed Li.
The field-ionization of a beam of high-Rydberg atoms
is shown to be a more sensitive probe of the field of a
surface-dipole layer than the deflection of an ion beam in
the same experimental geometry. Surface-dipole-moment
density measurements with a sensitivity of 6 x 10⁻⁵ ea₀ (1.5 x 10⁻⁴ debye) per adsorption site are within reach by
extending the experiments to principal quantum number
n = 80. The new technique, with its insensitivity to
surface roughness, promises to advance understanding of
surface ionization and van der Uaals forces as well as
provide measurements of adsorption rates, surface
densities, and dipole moments at sub-monolayer coverages.
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| Digitization Specifications |
- File scanned at 300 ppi (Monochrome) using ScandAll PRO 1.8.1 on a Fi-6670 in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
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| Additional Information |
- description.provenance : Approved for entry into archive by Deborah Campbell(deborah.campbell@oregonstate.edu) on 2013-07-02T16:55:43Z (GMT) No. of bitstreams: 1
TaylorCharlesR1988.pdf: 1263084 bytes, checksum: c80f31cb1c766b70789c3506330ed8a7 (MD5)
- description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2013-06-10T19:19:05Z (GMT) No. of bitstreams: 1
TaylorCharlesR1988.pdf: 1263084 bytes, checksum: c80f31cb1c766b70789c3506330ed8a7 (MD5)
- description.provenance : Made available in DSpace on 2013-07-02T16:55:43Z (GMT). No. of bitstreams: 1
TaylorCharlesR1988.pdf: 1263084 bytes, checksum: c80f31cb1c766b70789c3506330ed8a7 (MD5)
Previous issue date: 1987-06-03
- description.provenance : Submitted by Katy Davis (kdscannerosu@gmail.com) on 2013-06-03T19:46:32Z
No. of bitstreams: 1
TaylorCharlesR1988.pdf: 1263084 bytes, checksum: c80f31cb1c766b70789c3506330ed8a7 (MD5)
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