An alternative decoupled model is proposed to account for the correlated internal rotations in flexible alkyl chains of liquid crystals. Both gauche migration and gauche pair production in the chain are now taken into account. Spectral densities of motion for deuterons on various atomic sites in the chain are predicted and compared to the experimental values in the liquid crystal 4-n-hexyloxy-4'-cyanobiphenyl. Transition rates for the chain dynamics are discussed in conjunction with overall rotational diffusion constants.