Reorientational motions of the alkyl chains in C₁₀H₂₁ND₃Cl bidimensional crystal

INS experiments were performed at the Institut Laue-Langevin on the bidimensional C₁₀H₂₁ND₃Cl crystal to investigate the hydrocarbon chain motions through the various structural phases of the compound. The quasielastic profiles obtained on high and medium resolution spectrometers were refined simultaneously to get a reliable estimate of the elastic incoherent structure factors. In the high temperature phase, there is a gradient of disorder in the -CH₂-units on going from the polar head to the methyl ends in agreement with the "tree-like" structure suggested from previous Raman and infrared investigations.