We present a joint theoretical and experimental study to investigate polymorphism in α-sexithiophene (6T) crystals. By means of density-functional theory calculations, we clarify that the low-temperature phase is favorable over the high-temperature one, with higher relative stability by about 50 meV/molecule. This result is in agreement with our thermal desorption measurements. We also propose a transition path between the high- and low-temperature 6T polymorphs, estimating an upper bound for the energy barrier of about 1 eV/molecule. The analysis of the electronic properties of the investigated 6T crystal structures complements our study.
@article{arxiv.1602.04088,
title = {Polymorphism in $\alpha$-sexithiophene crystals: Relative stability and transition path},
author = {Bernhard Klett and Caterina Cocchi and Linus Pithan and Stefan Kowarik and Claudia Draxl},
journal= {arXiv preprint arXiv:1602.04088},
year = {2016}
}