Cover Image, Volume 113, Issue 18



Poly(3-hexylthiophene) is one of the most widespread conjugated polymers for organic electronics applications. Yet none of the atomistic models proposed for its crystal structure is fully satisfactory from a quantitative standpoint. Although the effect of the aliphatic side chains on crystal packing is now clear, it is common practice in theoretical investigations to approximate them to a rigid, fully extended arrangement or to shorten/remove them completely. In the cover article by Antonino Famulari et al. on page 2154, the conformational problem of a hexyl residue is tackled by quantum mechanical means without any a priori assumption but steric packing constraints.