Molecular Vibrations Are Not Asymmetric

2021 ◽  
pp. 000370282110365
Author(s):  
James A. de Haseth

There is considerable confusion when naming vibrations in infrared and Raman spectra. One of the most common errors is the identification of some stretching and bending vibrations as “asymmetric”. There are no asymmetric vibrations as such vibrations incur rotations and translations. The correct term is antisymmetric and it is demonstrated, through molecular symmetry operations, why this is the correct term.

1969 ◽  
Vol 23 (1) ◽  
pp. 12-16 ◽  
Author(s):  
Kosuke Shobatake ◽  
Clarence Postmus ◽  
John R. Ferraro ◽  
Kazuo Nakomoto

The infrared and Raman spectra of triphenyl compounds of Group VA elements PPh3, AsPh3, SbPh3, and BiPh3 (Ph represents the phenyl group), have been reported in the 530–100 cm−1 region. The metal-phenyl stretching and bending vibrations have been assigned with the aid of approximate normal coordinate analysis and depolarization ratios of Raman lines.


1979 ◽  
Vol 33 (4) ◽  
pp. 361-364 ◽  
Author(s):  
V. F. Kalasinsky ◽  
E. Block ◽  
D. E. Powers ◽  
W. C. Harris

The infrared and Raman spectra of 1,3-dithietane have been recorded with the sample in the solid state and trapped in an argon matrix at 18K. The number of coincidences between the infrared and Raman spectra of the matrix-isolated sample is consistent with C2v molecular symmetry in which the ring has a puckered conformation. In the solid state a number of bands disappear upon annealing, and the observed mutual exclusion for the annealed solid can be interpreted in terms of D2h, symmetry. Whereas the matrix probably represents the “free” molecule, the planarity of the ring in the annealed solid can be attributed to crystal packing.


1985 ◽  
Vol 63 (7) ◽  
pp. 1394-1398 ◽  
Author(s):  
Alain Lautié ◽  
Marie-France Lautié ◽  
Alexandre Novak

The infrared and Raman spectra of crystalline deltic acid and its deuterated derivative have been investigated in the 4000–20[Formula: see text]cm−1 range. An assignment of all the intramolecular fundamentals has been proposed assuming a C2v molecular symmetry. The crystal symmetry is likely to be described by the [Formula: see text] or P2/m space group with Z = 2. Deltic acid molecules probably form infinite chains linked with two very strong, asymmetric, and different OH … O hydrogen bonds, with O … O distances estimated at 2.49 and 2.56 Å.


1980 ◽  
Vol 35 (7) ◽  
pp. 792-796 ◽  
Author(s):  
Ralf Steudel ◽  
Jürgen Steidel ◽  
Norbert Rautenberg

A redetermination of the crystal and molecular structure of the chain-like molecule S(NSO)2 resulted in the following molecular parameters: d(SO) = 146.5(2), d(S = N) = 153.4(2), d(S-N) = 165.7(2) pm, bond angles OSN = 117.5(1)°, SNS = 123.6(2)°, and NSN = 97.2(1)°, torsion angles OSNS = -0.3(2)°, and SNSN = -177.7(2)° (molecular symmetry C2). Infrared and Raman spectra of S(NSO)2 are reported and assigned; there is no evidence for conformational changes on dissolution of crystalline S(NSO)2


1981 ◽  
Vol 46 (11) ◽  
pp. 2613-2619 ◽  
Author(s):  
Jiří Toužín

Available data on infrared and Raman spectra of S4N4 in solid state and solutions have been verified and completed. On the basis of normal coordinate analysis an attempt has been made to define with more precision the interpretation of vibration spectra of this compound given in earlier reports.


1990 ◽  
Vol 55 (6) ◽  
pp. 1485-1490 ◽  
Author(s):  
Peter Schwendt ◽  
Milan Sýkora

The infrared and Raman spectra of M2[V2O2(O2)4(H2O)]·xH2O and M2[V2O2(O2)4(D2O)]·xD2O (M = N(CH3)4, Cs) were measured. In the region of the vanadium-oxygen stretching vibrations, the spectra were interpreted based on normal coordinate analysis, employing empirical correlations between the bond lengths and force constants.


2007 ◽  
Vol 38 (9) ◽  
pp. 1159-1173 ◽  
Author(s):  
Gamil A. Guirgis ◽  
Paul M. Mazzone ◽  
Daniel N. Pasko ◽  
Peter Klaeboe ◽  
Anne Horn ◽  
...  

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