title: Polarized Raman spectroscopy of oligothiophene crystals to determine unit cell orientation.
abstract: Raman spectra were recorded experimentally and calculated theoretically for bithiophene, terthiophene, and quaterthiophene samples as a function of excitation polarization. Distinct spectral signatures were assigned and correlated to the molecular/unit cell orientation as determined by X-ray diffraction. The ability to predict molecular/unit cell orientation within organic crystals using polarized Raman spectroscopy was evaluated by predicting the unit cell orientation in a simulated terthiophene crystal given a random set of simulated polarized Raman spectra. Polarized Raman spectroscopy offers a promising tool to quickly and economically determine the unit cell orientation in known organic crystals and crystalline thin films. Implications of our methodologies for studying individual molecule conformations are discussed.
authors.affiliation: Department of Chemistry and Biochemistry and Center for Nano and Molecular Science, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Heckel
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Weisman
authors.forename: Severin T
authors.initials: ST
authors.lastname: Schneebeli
authors.forename: Michelle Lynn
authors.initials: ML
authors.lastname: Hall
authors.forename: Leif J
authors.initials: LJ
authors.lastname: Sherry
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Stranahan
authors.forename: Kateri H
authors.initials: KH
authors.lastname: DuBay
authors.forename: Richard A
authors.initials: RA
authors.lastname: Friesner
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Willets