Comparison of the maximum entropy and additive potential methods for obtaining rotational potentials from the NMR spectra of samples dissolved in liquid crystalline solvents. The case of 4-nitro-1-(.beta.,.beta.,.beta.-trifluoroethoxy)benzene

The maximum entropy (ME) and additive potential (AP) methods of determining the angular distribution functions, p(ω,χ), from the partially-averaged dipolar couplings obtained from the NMR spectra of liquid crystalline samples are compared. Here ω represents the orientation of the mesophase director in a molecular frame, and χ represents bond rotational motion. It is emphasized that these two methods are fundamentally different. Thus, the model-independent ME analysis can determine only p LC (ω,χ) and p LC (χ), which are dependent on the potential of mean torque, U ext (ω,χ), and the subscript LC denotes that these distributions are for the liquid-crystalline phase