Millimeter-wave spectra and revised spectroscopic parameters of methylsilane

Pelz, G.; Mittler, P.; Yamada, Kōichi; Winnewisser, G.

doi:10.1016/0022-2852(92)90240-o

Cited by 13 publications

(15 citation statements)

References 11 publications

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“…Finally, the rotational mode has not been observed but is expected from gas-phase spectra of methylsilane to have an excitation energy of about 200 cm −1 and a rotational barrier of ϳ590 cm −1 . 48 To our knowledge, the spectrum of the CD 3 -terminated surface has not been recorded, but the additional mass is expected to lower the vibrational frequencies based on gas-phase spectroscopy of isotopically substituted methylsilanes. 49 The perpendicular mean-square displacements arise from vibrational motion normal to the crystal surface.…”

Section: ͑9͒mentioning

confidence: 96%

Helium atom diffraction measurements of the surface structure and vibrational dynamics of CH3–Si(111) and CD3–Si(111) surfaces

Becker

Brown

Johansson

et al. 2010

The Journal of Chemical Physics

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The surface structure and vibrational dynamics of CH 3 -Si͑111͒ and CD 3 -Si͑111͒ surfaces were measured using helium atom scattering. The elastic diffraction patterns exhibited a lattice constant of 3.82 Å, in accordance with the spacing of the silicon underlayer. The excellent quality of the observed diffraction patterns, along with minimal diffuse background, indicated a high degree of long-range ordering and a low defect density for this interface. The vibrational dynamics were investigated by measurement of the Debye-Waller attenuation of the elastic diffraction peaks as the surface temperature was increased. The angular dependence of the specular ͑ i = f ͒ decay revealed perpendicular mean-square displacements of 1.0ϫ 10 −5 Å 2 K −1 for the CH 3 -Si͑111͒ surface and 1.2ϫ 10 −5 Å 2 K −1 for the CD 3 -Si͑111͒ surface, and a He-surface attractive well depth of ϳ7 meV. The effective surface Debye temperatures were calculated to be 983 K for the CH 3 -Si͑111͒ surface and 824 K for the CD 3 -Si͑111͒ surface. These relatively large Debye temperatures suggest that collisional energy accommodation at the surface occurs primarily through the Si-C local molecular modes. The parallel mean-square displacements were 7.1ϫ 10 −4 and 7.2ϫ 10 −4 Å 2 K −1 for the CH 3 -Si͑111͒ and CD 3 -Si͑111͒ surfaces, respectively. The observed increase in thermal motion is consistent with the interaction between the helium atoms and Si-CH 3 bending modes. These experiments have thus yielded detailed information on the dynamical properties of these robust and technologically interesting semiconductor interfaces.

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Section: ͑9͒mentioning

confidence: 96%

Helium atom diffraction measurements of the surface structure and vibrational dynamics of CH3–Si(111) and CD3–Si(111) surfaces

Becker

Brown

Johansson

et al. 2010

The Journal of Chemical Physics

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“…and ν 5 (a parallel band) and to identify perturbation-allowed transitions in the high overtones 3ν 6 and 5ν 6 (1,10,11). The perturbation-allowed transitions in turn provide very valuable additional constraints on the energies of the bath states.…”

Section: Introductionmentioning

confidence: 99%

“…In the current investigation, the torsional spectrum of CH 3 SiD 3 was recorded with the Bruker IFS120 HR interferometer that is coupled to the infrared beam line at the MAX-I synchrotron in Lund, Sweden. Using a long absorption path, high-resolution (0.002 cm −1 ) spectra of the torsional overtone 2ν 6 and the hot band 3ν 6 − ν 6 between 230 and 350 cm −1 were observed. Nearly 1300 frequencies in these two bands were assigned.…”

Section: Introductionmentioning

confidence: 99%

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High-Resolution Far-Infrared Torsional Spectrum of CH3SiD3 Using a Synchrotron Source

Schroderus

Horneman

Johnson

et al. 2002

Journal of Molecular Spectroscopy

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“…In the CD 3 -Si(111) case, the hindered rotation becomes the lowest-energy mode (16 meV) at theK-point after crossing the Rayleigh wave. The¯ -point hindered rotation energy of 29.0 meV for the CH 3 -Si(111) surface is slightly higher than the experimentally observed value of 24.8 meV for the CH 3 SiH 3 (methylsilane) molecule, 32 presumably due to the steric interaction between neighboring methyl groups on the surface, which are absent in the gas phase.…”

Section: Fig 3 Theoretical Dispersion Curves For Chmentioning

confidence: 54%

The interaction of organic adsorbate vibrations with substrate lattice waves in methyl-Si(111)-(1 × 1)

Brown

Hund

Campi

et al. 2014

The Journal of Chemical Physics

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A combined helium atom scattering and density functional perturbation theory study has been performed to elucidate the surface phonon dispersion relations for both the CH3-Si(111)-(1 × 1) and CD3-Si(111)-(1 × 1) surfaces. The combination of experimental and theoretical methods has allowed characterization of the interactions between the low energy vibrations of the adsorbate and the lattice waves of the underlying substrate, as well as characterization of the interactions between neighboring methyl groups, across the entire wavevector resolved vibrational energy spectrum of each system. The Rayleigh wave was found to hybridize with the surface rocking libration near the surface Brillouin zone edge at both the ${\rm \bar M}$M¯-point and ${\rm \bar K}$K¯-point. The calculations indicated that the range of possible energies for the potential barrier to the methyl rotation about the Si-C axis is sufficient to prevent the free rotation of the methyl groups at a room temperature interface. The density functional perturbation theory calculations revealed several other surface phonons that experienced mode-splitting arising from the mutual interaction of adjacent methyl groups. The theory identified a Lucas pair that exists just below the silicon optical bands. For both the CH3- and CD3-terminated Si(111) surfaces, the deformations of the methyl groups were examined and compared to previous experimental and theoretical work on the nature of the surface vibrations. The calculations indicated a splitting of the asymmetric deformation of the methyl group near the zone edges due to steric interactions of adjacent methyl groups. The observed shifts in vibrational energies of the -CD3 groups were consistent with the expected effect of isotopic substitution in this system.

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Millimeter-wave spectra and revised spectroscopic parameters of methylsilane

Cited by 13 publications

References 11 publications

Helium atom diffraction measurements of the surface structure and vibrational dynamics of CH3–Si(111) and CD3–Si(111) surfaces

Helium atom diffraction measurements of the surface structure and vibrational dynamics of CH3–Si(111) and CD3–Si(111) surfaces

High-Resolution Far-Infrared Torsional Spectrum of CH3SiD3 Using a Synchrotron Source

The interaction of organic adsorbate vibrations with substrate lattice waves in methyl-Si(111)-(1 × 1)

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