The long axis of the domains of 00ℓ intensity lies perpendicular to the major surface facet and is therefore aligned with the row of 00ℓ spots and the c*-axis. That is, the long axis of the domains aligns with the molecular chain axis. The average length of these domains determined across six fields of view was 332 nm (sample standard deviation s = 112 nm). For c = 8.26 nm, these lines correspond to approximately 40 unit cells packing together, i.e., 80 molecules packing end to end (s ~14 unit cells). These standard deviations refer to the width of the distribution of lengths rather than an uncertainty in the precision of their measurement.