Anharmonic Coupling Revealed by the Vibrational Spectra of Solvated Protonated Methanol: Fermi Resonance, Combination Bands, and Isotope Effect

2021 ◽  
Vol 125 (9) ◽  
pp. 1910-1918
Author(s):  
Chih-Kai Lin ◽  
Qian-Rui Huang ◽  
Ying-Cheng Li ◽  
Ha-Quyen Nguyen ◽  
Jer-Lai Kuo ◽  
...  
Keyword(s):  
Isotope Effect ◽  
Vibrational Spectra ◽  
Fermi Resonance ◽  
Anharmonic Coupling ◽  
Combination Bands

Anharmonic coupling behind vibrational spectra of solvated ammonium: lighting up overtone states by Fermi resonance through tuning solvation environments

2020 ◽  
Vol 22 (41) ◽  
pp. 24059-24069
Author(s):  
Chih-Kai Lin ◽  
Qian-Rui Huang ◽  
Jer-Lai Kuo
Keyword(s):  
Vibrational Spectra ◽  
Fermi Resonance ◽  
Anharmonic Coupling ◽  
Anharmonic Couplings

Fascinating Fermi resonance bands emerge from anharmonic couplings between NH stretching fundamentals and bending overtones in ammonium-centered clusters.

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.

Fermi Resonance Effects on the Vibration Modes of Hydrogen-Passivated Boron in Silicon

1989 ◽  
Vol 163 ◽  
Author(s):  
G.D. Watkins ◽  
W.B. Fowler ◽  
G.G. Deleo ◽  
M. Stavola ◽  
D.M. Kozuch ◽  
...  
Keyword(s):  
Second Harmonic ◽  
Fermi Resonance ◽  
Vibration Modes ◽  
Natural Explanation ◽  
Resonance Effects ◽  
Quantum Mechanical Treatment ◽  
Simple Quantum ◽  
Anharmonic Coupling ◽  
Quantitative Explanation ◽  
Direct Confirmation

Abstract10B - 11B isotope shifts have been reported recently for the vibrational frequencies of hydrogen (H) and its isotope deuterium (D) in the H-B complex in silicon. The D-10 B - D11 B shift was found to be anomalously large. We show that this effect finds a natural explanation in a phenomenon called “Fermi resonance”, arising from a weak anharmonic coupling between the second harmonic of the transverse B vibration and the longitudinal D vibration. We first present a simple classical explanation of the effect in terms of a “parametric oscillator”, or a child pumping a swing. We then outline a simple quantum mechanical treatment that provides a satisfactory quantitative explanation of the results. Our calculations also predict infrared absorption at the boron second harmonic frequencies. These are observed for both 10B and 11B with intensities and polarization as predicted, providing direct confirmation of the interpretation. The Pankove Si-H-B model, therefore, remains intact.

Infrared solvent shift studies. I. Acetylacetonates of some trivalent transition metals

1975 ◽  
Vol 28 (8) ◽  
pp. 1689 ◽  
Author(s):  
JYH Chau ◽  
P Hanprasopwattana
Keyword(s):  
Transition Metals ◽  
Crystal Field ◽  
Fermi Resonance ◽  
Electron Delocalization ◽  
Field Effects ◽  
Solvent Shift ◽  
Fe And Mn ◽  
Jahn Teller ◽  
Stretching Vibrations ◽  
Combination Bands

Solvent shift studies of MIII acetylacetonates where M = Co, Cr, Fe and Mn are reported in the 1700-1250 cm-1 region in about 20 solvents. Definitive assignments are made on fundamental C=O and C=C=C stretching vibrations. New solid bands are reported; these are probably due to combination bands, overtones, and ligand-crystal field effects. The possibility of Jahn-Teller effects, Fermi resonance, and the degree of π-electron delocalization in the chelate rings are discussed.

Isotope effect in the vibrational spectra of water measured in experiments with a scanning tunneling microscope

JETP Letters ◽  
1997 ◽  
Vol 66 (1) ◽  
pp. 37-40 ◽  
Author(s):  
M. V. Grishin ◽  
F. I. Dalidchik ◽  
S. A. Kovalevskii ◽  
N. N. Kolchenko ◽  
B. R. Shub
Keyword(s):  
Isotope Effect ◽  
Vibrational Spectra ◽  
Scanning Tunneling Microscope ◽  
Scanning Tunneling ◽  
Tunneling Microscope

Understanding Fermi resonances in the complex vibrational spectra of the methyl groups in methylamines

2021 ◽  
Vol 23 (6) ◽  
pp. 3739-3747
Author(s):  
Qian-Rui Huang ◽  
Tomoya Endo ◽  
Saurabh Mishra ◽  
Bingbing Zhang ◽  
Li-Wei Chen ◽  
...  
Keyword(s):  
Vibrational Spectra ◽  
Fermi Resonance ◽  
Methyl Groups ◽  
Spectral Features ◽  
Fermi Resonances

Vibrational spectra of the methyl groups in mono-methylamine (MMA), dimethylamine (DMA), and trimethylamine (TMA) monomers and their clusters were measured to capture their spectral features as a result of bend/umbrella-stretch Fermi resonance (FR).

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