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The NMR spectra of n-pentane as solute in the liquid crystal 5CB are measured at several temperatures in the nematic phase. Atomistic molecular dynamics simulations of this system are carried out to predict the dipolar couplings of the orientationally ordered pentane, and the spectra predicted from these simulations are compared with the NMR experimental ones. The simulation predictions provide an excellent starting point for analysis of the experimental NMR spectra using the covariance matrix adaptation evolutionary strategy. This shows both the power of atomistic simulations for aiding spectral analysis and the success of atomistic molecular dynamics in modeling these anisotropic systems. [ABSTRACT FROM AUTHOR]

Weemploy atomistic molecular dynamics simulations to predict thealignment and anchoring strength of a typical nematic liquid crystal,4-n-pentyl-4?-cyano biphenyl (5CB), on differentforms of silica. In particular, we study a thin (?20 nm) filmof 5CB supported on surfaces of crystalline (cristobalite) and amorphoussilica of different roughness. We find that the orientational orderat the surface and the anchoring strength depend on the morphologyof the silica surface and its roughness. Cristobalite yields a uniformplanar orientation and increases the order at the surface with respectto the bulk whereas amorphous glass has a disordering effect. Despitethe low order at the amorphous surfaces, a planar orientation is establishedwith a persistence length into the film higher than the one obtainedfor cristobalite. [ABSTRACT FROM AUTHOR]