Inherent structures of crystalline tetracene.
We have systematically sampled the potential energy surface of crystalline tetracene to identify its local minima. These minima represent all possible stable configurations and constitute the "inherent structures" of the system. The crystal is described in terms of rigid molecules with Coulombic and atom-atom interactions. Hundreds of distinct minima are identified, mostly belonging to the space groups P (triclinic) and P2(1)/c (monoclinic), with a variety of structural arrangements. The deepest minimum corresponds to the high temperature-low pressure polymorph. This is the only polymorph with a completely described X-ray structure, which is satisfactorily described by the calculations. The next deep minimum is likely to correspond to the low temperature-high pressure polymorph, which has been experimentally identified but not yet fully described.
Della Valle
Raffaele Guido
RG
Dipartimento di Chimica Fisica e Inorganica and INSTM-UdR Bologna, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy.
Venuti
Elisabetta
E
Brillante
Aldo
A
Girlando
Alberto
A