Density-functional Based Tight-binding Calculations on Thiophene Polymorphism. Issue 1 (2001)

• Record Type: Journal Article
• Authors: Widany, J.; Daminelli, G.; Di Carlo, A.; Lugli, P.
• Is Part Of: VLSI design. Volume 13:Issue 1/4(2001)
• Page Start: 393
• Page End: 397
• Publication Date: 2001
• Subjects: Organic semiconductors -- Oligothiophene -- Polymorphic crystals -- Intermolecular interaction -- Total energy calculations -- Density functional theory -- Tight-binding; Integrated circuits -- Very large scale integration -- Periodicals; 621.395
• DOI: 10.1155/2001/93289
• Languages: English
• ISSNs: 1065-514X

Abstract

Abstract : Total energy calculations based on a density-functional tight-binding scheme have been performed on polymorphic modifications of various thiophene crystals. The investigated structures include sulphanyl-substituted quater-thiophene and methyl-substituted sexithiophene, in the monoclinic and triclinic modifications. Attention has been focused on the intermolecular interaction between the molecular units. Despite the similarities in the backbone geometries, the strength and nature of intermolecular interaction differs largely in the various polymorphs. Sulphur atoms belonging to the thiophene rings are strongly involved in the interaction. Sulphanyl substituents play an important role, while methyl groups do not contribute. The strength of intermolecular interaction is not a direct function of atom distance.