On the structure and properties of polyamides. XX. Fermi resonance effects in vibrational spectra of N-methylacetamide

1965 ◽  
Vol 30 (7) ◽  
pp. 2215-2230 ◽  
Author(s):  
H. Pivcová ◽  
B. Schneider ◽  
J. Štokr
Keyword(s):  
Vibrational Spectra ◽  
Fermi Resonance ◽  
Structure And Properties ◽  
Resonance Effects

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

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.

Bromoselenate(II): Darstellung, Struktur und Eigenschaften von [P(C6H5)4]2SeBr4 und [P(C6H5)4]2Se2Br6 / Bromoselenates(II): Preparation, Structure and Properties of [P(C6H5)4]2SeBr4 and [P(C6H5)4]2Se2Br6

1984 ◽  
Vol 39 (12) ◽  
pp. 1633-1641 ◽  
Author(s):  
Bernt Krebs ◽  
Andreas Schäffer ◽  
Siegfried Pohl
Keyword(s):  
Bond Length ◽  
Vibrational Spectra ◽  
Acetonitrile Solution ◽  
The Novel ◽  
Structure And Properties ◽  
Subsequent Reaction ◽  
Space Group ◽  
X Ray ◽  
Square Planar ◽  
The Mean

The novel anion SeBr42- was prepared by dissociation of SeOBr2 with formation of SeBr2 and subsequent reaction with bromide in acetonitrile solution; it was isolated as the crystalline tetraphenylphosphonium salt. The X-ray structure analysis of [P(C6H 5)4]2SeBr4 (space group P 1̄ , a = 14.190(3), b = 15.125(3), c = 10.383(2) Å , α = 92.69(2), β = 100.89(2), γ = 92.04(2)° Å , V = 2182.2 Å3) shows the structure to contain monomeric SeBr42- anions with a square planar coordination of Se(II). The mean Se -Br bond length in the anion is 2.598 Å .[P(C6H5)4]2Se2Br6 was obtained from the reaction of SeBr4 (which is in equilibrium with SeBr2, Se2Br2, and Br2, in solution) and bromide in acetonitrile. It crystallizes in the space group P 1̄, with a = 1 0 . 9 3 3 ( 4 ) , = 11.154(4), c = 10.344(4) Å , α = 79.26(3), β = 72.63(3), y = 81.35(3)°, γ = 1176.7 Å3 (at -120 °C), and contains a novel type of centrosymmetric Se2Br62- ions with square planar Se-coordination. The mean terminal and bridging Se -Br bond lengths are 2.442 and 2.799 Å , resp. Vibrational spectra are reported and discussed.

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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