X-ray diffraction study of the structure of a monolayer methanol film adsorbed on graphite

Morishige, Kunimitsu; Kawamura, Kazuro; Köse, Ahmet

doi:10.1063/1.459645

Cited by 45 publications

(45 citation statements)

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“…Alcohols are known to form monolayers with unique properties on graphite. 43,44 HxOH is no exception, and it is observed to form a stable monolayer, in agreement with similar results for MeOH and BuOH. 37,38 The TOF distribution for D 2 O interacting with the HxOH/graphite system shows pronounced peaks for IS and TD.…”

Section: Resultssupporting

confidence: 92%

Water Accommodation on Ice and Organic Surfaces: Insights from Environmental Molecular Beam Experiments

et al. 2014

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Water uptake on aerosol and cloud particles in the atmosphere modifies their chemistry and microphysics with important implications for climate on Earth. Here, we apply an environmental molecular beam (EMB) method to characterize water accommodation on ice and organic surfaces. The adsorption of surface-active compounds including short-chain alcohols, nitric acid, and acetic acid significantly affects accommodation of D2O on ice. n-Hexanol and n-butanol adlayers reduce water uptake by facilitating rapid desorption and function as inefficient barriers for accommodation as well as desorption of water, while the effect of adsorbed methanol is small. Water accommodation is close to unity on nitric-acid- and acetic-acid-covered ice, and accommodation is significantly more efficient than that on the bare ice surface. Water uptake is inefficient on solid alcohols and acetic acid but strongly enhanced on liquid phases including a quasi-liquid layer on solid n-butanol. The EMB method provides unique information on accommodation and rapid kinetics on volatile surfaces, and these studies suggest that adsorbed organic and acidic compounds need to be taken into account when describing water at environmental interfaces.

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Section: Resultssupporting

confidence: 92%

Water Accommodation on Ice and Organic Surfaces: Insights from Environmental Molecular Beam Experiments

et al. 2014

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“…The lower value DS ð1Þ ¼ À6:7 cal/ mol K suggests a (2D) solid phase in the monolayer film. Then the ratio T m ð2DÞ T m ð3DÞ P 1:7 is greater than those determined for the CH 3 OH/graphite and C 2 H 5 OH/graphite systems, 0.8 [14] and 1.3 [15] respectively, and should be related to a high commensurability of the CH 3 OH thin films with the MgO(1 0 0) surface.…”

Section: Resultsmentioning

confidence: 92%

Thermodynamic and structural study of methanol thin films adsorbed on MgO(100)

et al. 2004

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“…Molecular orientation in such a pair of rows alternates from pair to pair. Although similar chain structures of hydrogen bonds are formed in both monolayer films of methanol [17] and ethanol [20,21] on graphite, a stacking sequence in the monolayer of A2-propanol is ABCD. .…”

mentioning

confidence: 94%

“…Breaking of the infinite chains of hydrogen bonds in the monolayer would lead to a loss of long-range order within the row constituted of the hydrogen-bonded head-to-head associations of the molecules while keeping quasi-long-range order between the rows. It remains puzzling, however, that both monolayers of methanol [17] and ethanol [20,21] having similar zigzag chains of hydrogen bonds do not show any evidence for formation of the 2D smectic mesophase.…”

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confidence: 98%

Occurrence of two-dimensional smectic liquid crystal inn-propanol adsorbed on graphite

1993

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X-ray diffraction illustrates that a two-dimensional smectic liquid crystal is formed in a melting process of an anisotropic, incommensurate monolayer of «-propanol physisorbed on graphite. In this phase a hydrogen-bonded head-to-head association of molecules is arranged in rows with their long axes on average normal to the row. Parallel to the rows, there is only short-range translational order of the molecules.PACS numbers: 61.10. My, 61.30.Eb, 64.70.Dv, 68.35.Rh The prediction of dislocation-mediated melting theory [1-3] that the melting of a two-dimensional (2D) solid could be fundamentally diflFerent from that observed in ordinary three-dimensional (3D) systems has caused a hot controversy among both theorists and experimentalists in the past decade [4][5][6][7][8][9][10][11][12]. Most of these studies, however, are concerned with isotropic monolayers and the melting of an anisotropic monolayer seems to have received little attention to date [7,8,10,13]. The theory [14] predicts that an anisotropic 2D solid composed of molecules which do not show mesophases in their 3D solid may melt via the two intermediate phases of twodimensional smectic and nematic liquid crystals. Recently, the 2D smectic mesophase has been observed at the interface between graphite and the melt of neat Az-alkanes by means of scanning tunneling microscopy [15,16]. As the nature of this system is strongly influenced by the molecules in the melt in contact with the monolayer, and the theory considers only the presence of an incommensurate crystalline substrate however, application of the 2D melting theory is difficult. Thus far the occurrence of the 2D smectic liquid crystal, which may permit a comparison with the 2D melting theory, has not been reported.In this Letter we report the results of an x-ray diffraction study of a monolayer AZ-propanol film on graphite. The results provide direct structural evidence that the 2D smectic mesophase occurs in the melting of an anisotropic, incommensurate monolayer of AZ-propanol physisorbed on graphite.

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X-ray diffraction study of the structure of a monolayer methanol film adsorbed on graphite

Cited by 45 publications

References 9 publications

Water Accommodation on Ice and Organic Surfaces: Insights from Environmental Molecular Beam Experiments

Water Accommodation on Ice and Organic Surfaces: Insights from Environmental Molecular Beam Experiments

Thermodynamic and structural study of methanol thin films adsorbed on MgO(100)

Occurrence of two-dimensional smectic liquid crystal inn-propanol adsorbed on graphite

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