Electron stimulated desorption of the metallic substrate at monolayer coverage: Sensitive detection via 193 nm laser photoionization of neutral aluminum desorbed from CH{sub 3}O/Al(111)
- Argonne National Lab., IL (United States)
- STI Optronics, Bellevue, WA (United States)
A fortuitous overlap between the gain profile of the 193 nm ArF excimer laser and the Al autoionizing transition {sup 2}S{sub 1/2} (512753 cm{sup {minus}1}) {l_arrow} {sup 2}P{sup 0}J has been exploited in the direct observation of substrate metal atoms in an electron simulated desorption (ESD) process from the monolayer adsorbate system CH{sub 3}O/Al(111). The identity of the mass 27 photoion was established as Al{sup +} by (1) isotopic substitution of {sup 13}C in the methanol employed for methoxy formation, and (2) tunable laser scans utilizing the {sup 2}DJ (J=3/2, 5/2) intermediate levels at {approximately}32436 cm{sup {minus}1} and a 248 nm ionization step. An ESD yield of {approximately}{times}10{sup {minus}6} Al atoms/(electron at 1 keV) was established by comparison with a sputtering experiment in the same apparatus. Velocity distributions measured for the desorbed Al species showed some differences in comparison with methoxy velocity data: a slightly lower peak velocity and a significantly less prominent high-velocity component. 10 refs., 4 figs.
- Research Organization:
- Argonne National Lab., IL (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 10148459
- Report Number(s):
- ANL/CP--75386; CONF-920462--2; ON: DE92014858
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
426002
665300
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM
DESORPTION
ELECTRON-ATOM COLLISIONS
EV RANGE 100-1000
EXCIMER LASERS
HABIT PLANES
INTERACTIONS BETWEEN BEAMS AND CONDENSED MATTER
LASERS AND MASERS
MASS SPECTROMETERS
METHOXY RADICALS
PHOTOIONIZATION
PULSED IRRADIATION
SPUTTERING
TIME-OF-FLIGHT METHOD