Figure also shows the relative populations for molecules with the C-N vector pointing "up" (red) or "down" (blue) along the z-axis, which corresponds to molecules having their alkyl chains below or above the aromatic moiety, respectively, along this axis (as illustrated schematically in Figure and). In Figure , the head-group atoms of 8OCB and 9, and the tail-group atoms of 8OCB, show only a small difference in the relative populations of the "up" and "down" molecules along the z-axis, which indicates a significant degree of interdigitation of the aromatic head-groups of 8OCB and 9, and of the linear alkyl tail groups of 8OCB. By contrast, the cyclic tail-group atoms of 9 show relative populations of "up" and "down" molecules that are distinctly offset along the z-axis, with the "up" molecules (cyclohexyl group at the bottom) being higher on the z-axis than that of the "down" molecules (cyclohexyl group at the top), which indicates a relatively low degree of interdigitation for the cyclic tail groups of 9. The distributions shown in Figure were used to quantify the extent of interdigitation. The C4′ biphenyl head group atoms of 8OCB and 9 showed 50% and 53% interdigitation, respectively, corresponding to approximately half of these head-group atoms being located in the adjacent layer. The C8 alkyl tail group atoms of 8OCB showed 50% interdigitation, similar to the head groups, whereas the C4 cyclohexyl tail group atoms of 9 showed a much lower interdigitation of 39%. Hence, 8OCB shows a similar extent of interdigitation at both ends of the molecule, whereas 9 shows much less interdigitation of the bulky cyclohexyl tail group than the biphenyl head group. This behaviour is similar to that reported previously for 11OCB and t-Bu-11OCB, where the bulky t-Bu tail group displayed less interdigitation than the other terminal groups in either system.