On the Interpretation of the 1100 cm ⁻¹ Raman Band in Phospholipids and Other Alkyl-Containing Molecular Entities

The long-standing issue on the interpretation of a Raman band at 1100 cm(-1) is discussed. By combining observations from studies on lipid bilayers, alkanes, and polyethylenes, one can now definitely assign this band to the presence of isolated gauche bonds. In addition, we discuss the use of an order parameter S(trans) in lipid bilayer structures.