Temperature studies of the low-frequency Raman spectra of crystalline molecular complexes

1970 ◽  
Vol 10 (6) ◽  
pp. 1005-1007
Author(s):  
A. V. Korshunov ◽  
V. F. Shabanov ◽  
V. E. Volkov
Keyword(s):  
Raman Spectra ◽  
Low Frequency ◽  
Molecular Complexes

Low-frequency Raman spectra in crystalline molecular complexes

1970 ◽  
Vol 10 (5) ◽  
pp. 715-718 ◽  
Author(s):  
V. E. Volkov ◽  
V. F. Shabanov ◽  
A. V. Korshunov
Keyword(s):  
Raman Spectra ◽  
Low Frequency ◽  
Molecular Complexes

Low frequency Raman spectra of the liquid and plastic crystal phases of O2, N2, CO, and of Ar crystals with these molecules as guests

1982 ◽  
Vol 60 (9) ◽  
pp. 1358-1364 ◽  
Author(s):  
N. H. Rich ◽  
M. J. Clouter ◽  
H. Kiefte ◽  
S. F. Ahmad
Keyword(s):  
Single Crystals ◽  
Raman Spectra ◽  
Phonon Mode ◽  
Low Frequency ◽  
Impurity Molecule ◽  
Spectral Features ◽  
Background Impurity ◽  
Crystal Phases ◽  
Distinct Features ◽  
Frequency Feature

Low frequency Raman spectra of single crystals of orientationally disordered phases of oxygen, nitrogen, and carbon monoxide, and spectra of those substances as liquids show two linear segments in semi-log plots. Slopes of the higher frequency segments are nearly equal for all cases; slopes of the lower frequency segments are particular to the substance and are nearly the same in both liquid and crystal for O2 and CO. Spectra of single crystals of argon doped with O2, N2, or CO show two distinct features superimposed on a sloping background. Impurity molecule reorientation apparently accounts satisfactorily for all spectral features, but translation–rotation coupling may allow a contribution to the higher frequency feature arising from a local phonon mode in argon.

Donor-acceptor complexes formed by perfluoro-organo bromides and iodides with nitrogenous and other bases. II. Band shapes and widths in the absorption spectrum of gaseous CF3I-N(CH3)3

1971 ◽  
Vol 24 (12) ◽  
pp. 2493 ◽  
Author(s):  
A Mishra ◽  
ADE Pullin
Keyword(s):  
Vibrational Mode ◽  
Low Frequency ◽  
Molecular Complexes ◽  
Wave Number ◽  
Centrifugal Distortion ◽  
Band Shape ◽  
Gaseous Mixtures ◽  
Factors Affecting ◽  
Donor Acceptor ◽  
Vibration Rotation

The absorption band centred at c. 77 cm-1 in gaseous mixtures of CF3I and N(CH3)3 previously reported and attributed to the N-I stretching mode of the complex CF3I-N(CH3)3 has been carefully re-examined. This band is of interest as an example of a low frequency ?dissociative type? vibrational mode of a weak molecular complex. The band is asymmetric and apparently structureless with a half intensity width at room temperature of 28-30 cm-1. The width of the band may be accounted for as arising from transitions vi + vi+1 where vi is the vibrational quantum number of the N-I stretching mode with vi up to c. 10 making appreciable contribution to the intensity on the low wave-number side. Centrifugal distortion in the complex is considered. Centrifugal stretching and consequent weakening of the bond may shift the band envelope 2-3 cm-1 to lower wave numbers. Assessment of these and other factors affecting the band shape suggest that the fundamental frequency is probably c. 90 cm-1. The band shape of the vibrational mode of the complex at c. 272 cm-1 is briefly discussed. Many of the considerations presented in this paper should apply to vibration-rotation band shapes in other weak molecular complexes. Some general consequences of anharmonicity for the interpretation of the spectra of weak molecular complexes are discussed.

Polytypic structure and low-frequency Raman spectra of long-chain compounds: Stearic acid E form

1993 ◽  
Vol 24 (8) ◽  
pp. 527-532 ◽  
Author(s):  
Fumitoshi Kaneko ◽  
Masamichi Kobayashi ◽  
Hirotoshi Sakashita
Keyword(s):  
Stearic Acid ◽  
Raman Spectra ◽  
Low Frequency ◽  
Chain Compounds ◽  
Long Chain

scholarly journals Комбинационное рассеяние света в хирально чистых и рацемической фазах поликристаллов триптофана и тирозина

2019 ◽  
Vol 127 (10) ◽  
pp. 541
Author(s):  
В.С. Горелик ◽  
М.Ф. Умаров ◽  
Ю.П. Войнов
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Raman Spectra ◽  
Spectral Range ◽  
Phase State ◽  
Source Parameters ◽  
Low Frequency ◽  
Aromatic Amino Acids ◽  
Chiral Phase ◽  
Left Handed

AbstractRaman spectra of tryptophan and tyrosine polycrystals have been analyzed in a wide spectral range by fiber-optic spectroscopy. The Raman spectra have been recorded with a BWS465-785H spectrometer in the spectral range of 0–2700 cm^–1 using a 785-nm cw laser as an excitation source. Parameters of the Raman spectra are compared for three crystalline phase modifications of aromatic amino acids: left-handed, right-handed, and racemic phase. The presence of strong Raman satellites, the characteristics of which change depending on the type of the chiral phase state of amino acid, is found in the low-frequency Raman spectra of tryptophan and tyrosine amino acid lattices. The results obtained can be used for monitoring the chiral purity of bioactive preparations containing amino acids.

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