ISSN:
1432-0630
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract The adsorption of oxygen and hydrogen on a Pt(111) surface has been studied with phase-sensitive Second-Harmonic Generation (SHG) signal detection. The SHG-signal change measured with p-in, p-out polarization during the adsorption of oxygen and hydrogen was found to be different in amplitude and phase for the two adsorbates. At the wavelength used (1064 nm), only a localized interaction between adsorbate and substrate is seen, leading to a linear dependence of the susceptibility on the coverage. Sticking coefficients, $s_\theta$ , and their coverage dependence were determined. For hydrogen, a linear decrease in $s _\theta$ with coverage was found; the initial sticking coefficient being $s_0= 0.06$ at a temperature of $T = 130$ K. For oxygen, $s_\theta$ shows a quadratic decrease with coverage, strongly dependent on temperature, with $s_0=0.05$ at $T = 350$ K. A method based on these results is proposed, which would allow the determination of adsorbate coverages of coadsorption systems with SHG using phase-sensitive signal detection. PACS68.35; 82.20; 42.65
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003390050092
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