Desorption of Benzene, 1,3,5-Trifluorobenzene, and Hexafluorobenzene from a Graphene Surface: The Effect of Lateral Interactions on the Desorption Kinetics

Journal Article · Thu May 17 04:00:00 EDT 2018 · The Journal of Physical Chemistry Letters

DOI:https://doi.org/10.1021/acs.jpclett.8b00986· OSTI ID:1526039

Smith, Ronald S. ^[1]; Kay, Bruce D. ^[1]

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1. BATTELLE (PACIFIC NW LAB)

The desorption of benzene, 1,3,5-trifluorobenzene (TFB), and hexafluorobenzene (HFB) from a graphene covered Pt(111) substrate was investigated using temperature programmed desorption (TPD). All three species have well-resolved monolayer and second layer desorption peaks. The desorption spectra for submonolayer coverages of benzene and hexafluorobenzene are consistent with first-order desorption kinetics. In contrast, the submonolayer TPD spectra for 1,3,5- trifluorobenzene align on a common leading-edge which is indicative of zero-order desorption kinetics. The desorption behavior of the three molecules can be correlated with the strength of the quadrupole moments. Calculations (second-order Møller-Plesset perturbation and density functional theory) show that the potential minimum for coplanar TFB dimers is more than a factor of two greater than that for either benzene or HFB dimers. The calculations support the interpretation that benzene and HFB are less likely to form the two-dimensional islands that are needed for submonolayer zero-order desorption kinetics.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1526039
• Report Number(s): PNNL-SA-131963
• Journal Information: The Journal of Physical Chemistry Letters, Journal Name: The Journal of Physical Chemistry Letters Journal Issue: 10 Vol. 9
• Country of Publication: United States
• Language: English