Discerning Inter- and Intramolecular Vibrations of Sulfur Polyaromatic Compounds

Abstract : Thiophenes are an important class of moleculesinfields as diverse as petrochemistry, molecular electronics, andoptoelectronics. Thiophenic submolecular motifs are thought toplay a role in molecular association and nanoaggregationphenomena in both pure materials and natural and syntheticmixtures. Vibrational (infrared and Raman) spectroscopyprovides the means to characterize these species. In this workfar-infrared photoacoustic and low-frequency Raman spectra ofa series of polycyclic aromatic hydrocarbons containing sulfur have been measured and interpreted using DFT calculations basedon a perturbational-variational method coupled with potential truncation. The approach and outcomes illustrate how inter- andintramolecular vibrations for thiophenic systems in single and multicomponent mixtures can be discriminated. This work offersthe perspective to search the inter- and intramolecular signatures of the main submolecular motifs and heteroelements postulatedas being present in the asphaltenes.