RAMAN STUDIES OF THE C=C AND C=O STRETCHING MODES IN VARIOUS CHOLESTERYL ALKANOATES

Cholesteryl alkanoates were previously mostly studied by biochemists, and more rarely by physicists. In this work we present Raman studies o f the C=C and C=O stretching modes for various cholesteryl alkanoates after different treatments. The unicity of these bonds in theses molec ules permits us to propound the C=C stretching mode as an internal ref erence in regard to its independence from the alkyl chain length. The splitting of the C=O stretching mode leads us to conclude on the exist ence of two types of molecules, differing only by angle and bond-lengt h variations, in the polycrystalline state.