title: Polymorphism in α-sexithiophene crystals: relative stability and transition path.
abstract: 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 up to 50 meV per 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 per molecule. The analysis of the electronic properties of the investigated 6T crystal structures complements our study.
authors.affiliation: Institut für Physik, Humboldt-Universität zu Berlin, Berlin, Germany. caterina.cocchi@physik.hu-berlin.de.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Klett
authors.forename: Caterina
authors.initials: C
authors.lastname: Cocchi
authors.forename: Linus
authors.initials: L
authors.lastname: Pithan
authors.forename: Stefan
authors.initials: S
authors.lastname: Kowarik
authors.forename: Claudia
authors.initials: C
authors.lastname: Draxl