Adsorption of (formula presented) on nickel clusters at high temperature

Physical Review B - Condensed Matter and Materials Physics

Volumn 59, Issue 20, 1999, Pages 13431-13445

  Winter, B J ^b   Kerns, K P ^a   Riley, S J ^a  

^a ARGONNE NATIONAL LABORATORY   (United States)

^b MAX BORN INSTITUT   (Germany)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0001448792     PISSN: 10980121     EISSN: 1550235X     Source Type: Journal    
DOI: 10.1103/PhysRevB.59.13431     Document Type: Article

References (68)

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22. As an example, with the FTR at 1073 K, a (Formula presented) cluster emerges from the nozzle expansion with roughly 70 eV of translational energy along the cluster beam axis. This energy was determined by modeling the mass spectrometer with the program MACSIMION and determining the energy from the experimentally determined deflection plate voltage settings for (Formula presented)
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26. The value of 18 mTorr is best considered an upper limit. The average He flow velocity in the FTR was used in determining the (Formula presented) pressure. Since the (Formula presented) distribution across the diameter of the FTR is to some extent concentrated in the center (where the He flow velocity is twice the average), the (Formula presented) flow velocity is somewhere between the average He flow velocity and twice that velocity. As a result, the (Formula presented) pressure is likely somewhat lower than 18 mTorr but certainly greater than 10 mTorr. At the cup temperature that produces the nominal (Formula presented) vapor pressure, the static vapor pressure above solid (Formula presented) is ∼1.1 Torr [extrapolated from the data of J. Abrefah, D. R. Olander, M. Balooch, and W. J. Siekhaus, Appl. Phys. Lett. 60, 1313 (1992)]. The nominal vapor pressure in the FTR is lower due to the low rate of diffusion of (Formula presented) out of the cup into the helium carrier gas. To monitor the (Formula presented) pressure in the present experiments, the (Formula presented) ion signal in the mass spectrum was followed over the lifetime of the sample in the cup.
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37. Unpublished results from this laboratory.
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