Anharmonic coupling effects among adsorbate vibrational modes: The model system Ru (001)-( $\sqrt{3}$ × $\sqrt{3}$ )R30°-CO revisited

2002 ◽  
Vol 75 (1) ◽  
pp. 45-57 ◽  
Author(s):  
P. Jakob
Keyword(s):  
Model System ◽  
Vibrational Modes ◽  
Coupling Effects ◽  
Anharmonic Coupling

Revealing Suppressed Intermolecular Coupling Effects in Aggregated Organic Semiconductors by Diluting the Crystal: Model System Perfluoropentacene:Picene

2019 ◽  
Vol 123 (32) ◽  
pp. 7016-7020
Author(s):  
Johannes Dieterle ◽  
Katharina Broch ◽  
Alexander Hinderhofer ◽  
Heiko Frank ◽  
Alexander Gerlach ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Model System ◽  
Coupling Effects ◽  
Crystal Model ◽  
Intermolecular Coupling

Hydrogen Local Vibrational Modes in Compound Semiconductors

1998 ◽  
Vol 513 ◽  
Author(s):  
M. D. Mccluskey
Keyword(s):  
Hydrostatic Pressure ◽  
Resonant Interaction ◽  
Host Lattice ◽  
Local Mode ◽  
Vibrational Modes ◽  
Temperature Dependent ◽  
Local Vibrational Mode ◽  
Combination Modes ◽  
Stretch Mode ◽  
Anharmonic Coupling

ABSTRACTLocal vibrational mode (LVM) spectroscopy of hydrogen and deuterium in GaP, AlSb, ZnSe, and GaN has provided important information about the structures of dopanthydrogen complexes and their interaction with the host lattice. In GaN:Mg, for example, hydrogen binds to a host nitrogen which is adjacent to the magnesium acceptor. In GaP and ZnSe, it has been demonstrated that the temperature dependent shifts of LVM's are proportional to the lattice thermal energy, a consequence of the anharmonic coupling of the local mode to acoustical phonons.Large hydrostatic pressures have been applied to semiconductors to probe the vibrational properties of hydrogen-related complexes. In GaAs, the pressure dependent shifts of the 12C-H and 13C-H stretch modes have positive curvatures, while the shift of the S-H stretch mode has a negative curvature. This may be related to the fact that in the bond-centered C-H complex, the hydrogen is compressed between the carbon acceptor and one gallium host atom, whereas in the S-H complex, the hydrogen occupies an interstitial position and is not crowded by neighboring atoms. If these trends are general, then hydrostatic pressure may be a powerful tool in determining the position of the hydrogen atom(s) in a complex.In AISb. pressure was utilized to resolve a mystery as to why the Se-D complex gives rise to one stretch mode peak while the Se-H stretch mode splits into three peaks. This anomalous splitting is explained in terms of a new resonant interaction between the stretch mode and combination modes involving a wag mode harmonic and extended lattice phonons. The interaction gives rise to vibrational modes with both localized and extended components. When the temperature or hydrostatic pressure is varied, the modes exhibit anti-crossing behavior.

scholarly journals Ultrafast Vibrational Dynamics of CO Ligands on RuTPP/Cu(110) under Photodesorption Conditions

Surfaces ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 117-130 ◽  
Author(s):  
Takuma Omiya ◽  
Yousoo Kim ◽  
Rasmita Raval ◽  
Heike Arnolds
Keyword(s):  
Low Frequency ◽  
Blue Shift ◽  
Vibrational Modes ◽  
Vibrational Dynamics ◽  
Sum Frequency ◽  
Stretching Vibration ◽  
A Charge ◽  
Anharmonic Coupling ◽  
Vibration Coupling ◽  
Probe Spectroscopy

We have studied CO coordinated to ruthenium tetraphenylporphyrin (RuTPP)/Cu(110) and directly adsorbed to Cu(110), using femtosecond pump-sum frequency probe spectroscopy, to alter the degree of electron-vibration coupling between the metal substrate and CO. We observe the facile femtosecond laser-induced desorption of CO from RuTPP/Cu(110), but not from Cu(110). A change in the vibrational transients, in the first few picoseconds, from a red- to blue-shift of the C–O stretching vibration under photodesorption conditions, was also observed. This drastic change can be explained, if the cause of the C–O frequency redshift of Cu(110) is not the usually-assumed anharmonic coupling to low frequency vibrational modes, but a charge transfer from hot electrons to the CO 2π* state. This antibonding state shifts to higher energies on RuTPP, removing the C–O redshift and, instead, reveals a blueshift, predicted to arise from electron-mediated coupling between the coherently excited internal stretch and low frequency modes in the system.

scholarly journals Coherent two-dimensional terahertz-terahertz-Raman spectroscopy

2016 ◽  
Vol 113 (25) ◽  
pp. 6857-6861 ◽  
Author(s):  
Ian A. Finneran ◽  
Ralph Welsch ◽  
Marco A. Allodi ◽  
Thomas F. Miller ◽  
Geoffrey A. Blake
Keyword(s):  
Raman Spectroscopy ◽  
Liquid Phase ◽  
Hybrid Approach ◽  
Vibrational Modes ◽  
Two Dimensional ◽  
Thermally Activated ◽  
Isotropic Media ◽  
Multiple Pulses ◽  
Anharmonic Coupling ◽  
Phase Chemistry

We present 2D terahertz-terahertz-Raman (2D TTR) spectroscopy, the first technique, to our knowledge, to interrogate a liquid with multiple pulses of terahertz (THz) light. This hybrid approach isolates nonlinear signatures in isotropic media, and is sensitive to the coupling and anharmonicity of thermally activated THz modes that play a central role in liquid-phase chemistry. Specifically, by varying the timing between two intense THz pulses, we control the orientational alignment of molecules in a liquid, and nonlinearly excite vibrational coherences. A comparison of experimental and simulated 2D TTR spectra of bromoform (CHBr3), carbon tetrachloride (CCl4), and dibromodichloromethane (CBr2Cl2) shows previously unobserved off-diagonal anharmonic coupling between thermally populated vibrational modes.

Ab Initio Study of Vibrational Anharmonic Coupling Effects in Oligo(para-phenylenes)

2001 ◽  
Vol 708 ◽  
Author(s):  
G. Heimel ◽  
D. Somitsch ◽  
P. Knoll ◽  
E. Zojer
Keyword(s):  
Quantum Chemical ◽  
Fermi Resonance ◽  
Semiempirical Methods ◽  
Quantum Mechanical ◽  
Ab Initio Study ◽  
Coupling Effects ◽  
Anharmonic Coupling ◽  
Combination Bands ◽  
Ab Inito ◽  
Anharmonic Force

ABSTRACTIn this study we present a theoretical approach to simulate vibrational anharmonic coupling effects seen in the Raman spectra of oligo(para-phenylenes). Quantum chemical ab inito methods are applied to determine anharmonic force constants and energy corrections on the harmonic vibrational frequencies of the isolated molecules. Semiempirical methods are applied to compute Raman intensities of fundamentals and combination bands. This methodology is then used to characterize a previously unassigned Fermi resonance around 1600 cm-1. The evolution of this quantum mechanical resonance with oligomer length and planarity is compared to experimental data.

Ab initio study of vibrational anharmonic coupling effects in oligo(para-phenylenes)

2002 ◽  
Vol 116 (24) ◽  
pp. 10921-10931 ◽  
Author(s):  
G. Heimel ◽  
D. Somitsch ◽  
P. Knoll ◽  
E. Zojer
Keyword(s):  
Ab Initio ◽  
Ab Initio Study ◽  
Coupling Effects ◽  
Anharmonic Coupling

IR-active vibrational modes of CdTe and CdSe colloidal quantum dots and CdTe/CdSe core/shell nanoparticles and coupling effects

2007 ◽  
Vol 49 (3) ◽  
pp. 547-551 ◽  
Author(s):  
R. B. Vasiliev ◽  
V. S. Vinogradov ◽  
S. G. Dorofeev ◽  
S. P. Kozyrev ◽  
I. V. Kucherenko ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Colloidal Quantum Dots ◽  
Core Shell ◽  
Vibrational Modes ◽  
Coupling Effects ◽  
Cdse Core ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles

A Protozoan Model for Golgi-Associated Calcification

1971 ◽  
Vol 29 ◽  
pp. 332-333
Author(s):  
D. C. Williams ◽  
D. E. Outka
Keyword(s):  
Golgi Apparatus ◽  
Organic Matrix ◽  
Model System ◽  
Sequential Formation

Many studies have shown that the Golgi apparatus is involved in a variety of synthetic activities, and probably no Golgi product is more elaborate than the scales produced by various kinds of phytoflagellates. The formation of calcified scales (coccoliths, Fig. 1,2) of the coccolithophorid phytoflagellates provides a particularly interesting model system for the study of biological mineralization, and the sequential formation of Golgi products.The coccoliths of Hymenomonas carterae consist of a scale-like base (Fig. 2 and 4, b) with a highly structured calcified (CaCO3) rim composed of two distinct elements which alternate about the base periphery (Fig. 1 and 3, A, B). Each element is enveloped by a sheath-like organic matrix (Fig. 3; Fig. 4, m).

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