I was moaning to a PhD student in the group about the perennial issue of checking representative torsional conformers of oligomers. In this case it was the question about whether you’d see a large variation in oscillator strength (of a TDDFT calculation) if you change the conformation (we don’t see a big variation in the energies of excited states, unless you break conjugation). This is a genuine issue as the potential energy barrier for these torsional variations are thermally accessible, and typically presents at least two local minima (head-tail and head-head), if not 4 minima (where the flat alignments are sterically hindered), so real polymers will be sampling at least some of these structures.