Figure 7. A sufficiently large population of αTm molecules is required for reliable measurement of L_p.

L_p was calculated for each of 200 subsets of N αTm (N = 10, 20, 40…) randomly selected from a total of 1852 molecules. The mean L_p is plotted against N. A consistent overestimation of L_p up to 8 nm was observed for small N (<80–160). This overestimation can be attributed to the biased distribution of contour shapes, where highly bent configurations of the molecule are relatively rare. In case of small N, therefore, the highly bent configurations are under- or un-sampled, which leads to overestimation of L_p based on a biased population of relatively straight molecules.