Anharmonic adlayer vibrations on the Si(111):H surface

Honke, R.; Jakob, Peter M.; Chabal, Yves J.; Dvorák, Alexander; Tausendpfund, S.; Stigler, W.; Pavone, P.; Mayer, Andreas; Schröder, U.

doi:10.1103/physrevb.59.10996

Cited by 35 publications

(23 citation statements)

References 66 publications

(71 reference statements)

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“…However, in spite of the great interest that these classical nonlinear objects have attracted, no clear evidence has been found for their existence in real lattices. By contrast, TVBS are have been observed in several low-dimensional molecular lattices [20,21,22,23,24,25,26,27,28]. These quantum objects correspond to the first quantum states which experience the nonlinearity and can thus be viewed as the quantum counterpart of breathers or soliton excitations [12].…”

Section: Introductionmentioning

confidence: 99%

Relaxation channels of two-vibron bound states in α-helix proteins

Pouthier

Falvo

2004

Phys. Rev. E

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Relaxation channels for two-vibron bound states in an anharmonic α-helix protein are studied. According to a recently established small polaron model [V. Pouthier, Phys. Rev. E68, 021909 (2003)], it is pointed out that the relaxation originates in the interaction between the dressed anharmonic vibrons and the remaining phonons. This interaction is responsible for the occurrence of transitions between two-vibron eigenstates mediated by both phonon absorption and phonon emission. At biological temperature, it is shown that the relaxation rate does not significantly depends on the nature of the two-vibron state involved in the process. Therefore, the lifetime for both bound and free states is of the same order of magnitude and ranges between 0.1 and 1.0 ps for realistic parameters. By contrast, the relaxation channels strongly depend on the nature of the two-vibron states which is a consequence of the breather-like behavior of the two-vibron bound states.

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Section: Introductionmentioning

confidence: 99%

Relaxation channels of two-vibron bound states in α-helix proteins

Pouthier

Falvo

2004

Phys. Rev. E

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“…33 These modes have been predicted and observed for the H-Si(111)-(1 × 1) surface with an energy at the¯ -point ranging from 58.7 to 62 meV. [34][35][36] The results of our calculations indicated that for the methylated Si(111) surface, the Lucas pair is degenerate at the¯ -point, as required by symmetry, and then splits as it evolves toward the SBZ edges. The longitudinal component hybridizes with the continuum of longitudinal bulk modes, transforming into a broad resonance, while the shear horizontal mode partially hybridizes with the shear vertical vibrations of the carbon atom and maintains a well-defined surface character throughout the SBZ.…”

Section: Fig 3 Theoretical Dispersion Curves For Chmentioning

confidence: 70%

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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“…Experimentally, a particular emphasis was on the dynamics of the Si-H stretch mode [1,[26][27][28][29][30][31][32]. The stretching vibration is a high-frequency mode with xðSi À HÞ > 2000 cm À1 , which decays on a typical timescale of ns (10 À9 s) into a combination of Si-H bending excitations, and lattice phonons [1,12], the latter characterized by a Debye frequency of around 520 cm À1 .…”

Section: Introductionmentioning

confidence: 99%