Assignment of the CH stretching vibrational frequencies in the Raman spectra of lipids

✍ Scribed by Rosalind Faiman; Kåre Larsson

• Publisher: John Wiley and Sons
• Year: 1976
• Tongue: English
• Weight: 389 KB
• Volume: 4
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/jrs.1250040406

✦ Synopsis

Abstract

A Raman spectroscopic study of several substituted lipids lacking a methyl end group has been carried out in order to assign the vibrational CH stretching modes, all of which arise from the methylene group vibrations. Polarization measurements on the melt and cubic liquid crystalline phase show that the peak in the region of 2885±5 cm^−1^ is rather weakly polarized in the liquid and liquid crystalline phases, whereas the peak at 2850 cm^−1^ is rather strongly polarized. Thus it is concluded that the 2850 cm^−1^ peak arises mainly from the methylene symmetric stretching modes and the 2885±5 cm^−1^ peak arises mainly from the methylene antisymmetric stretching modes. The band at about 2930 cm^−1^ is assigned to a symmetric methylene stretching vibration. The implications in the interpretation of chain mobility and chain conformation are discussed.