Vibrational correlation splitting and chain packing for the crystalline n-alkanes

Vibrational correlation-splitting patterns for the infrared active methylene rocking–twisting fundamentals of the orthorhombic and monoclinic n-alkanes have been determined and analyzed. Polarization measurements show that the splitting patterns are different for the two structures. A simple two parameter coupled oscillator model accounts for the observed shapes of the c axis dispersion curves. It is suggested that the results of this analysis may be useful in establishing the type of packing involved in crystals containing long-chain hydrocarbon molecules.