title: Polymorphism and phonon dynamics of alpha-quaterthiophene.
abstract: Low-frequency (10-150 cm(-1)) Raman spectra of the low-temperature (LT) and high-temperature (HT) polymorphs of the organic semiconductor alpha-quaterthiophene at 300 and 10 K are reported. Polarized spectra, assisted by quasi-harmonic lattice dynamics (QHLD) calculations, allow characterization of the lattice phonon dynamics and identification of the two phases spectroscopically. The experimental data can be explained by taking into account the coupling between intermolecular (lattice) and low-frequency intramolecular modes. Finally, Raman mapping is used to investigate the phase purity.
authors.affiliation: Dip. Chimica G.I.A.F. and INSTM-UdR Parma, Università di Parma, 43100 Parma, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Ranzieri
authors.forename: Alberto
authors.initials: A
authors.lastname: Girlando
authors.forename: Silvia
authors.initials: S
authors.lastname: Tavazzi
authors.forename: Marcello
authors.initials: M
authors.lastname: Campione
authors.forename: Luisa
authors.initials: L
authors.lastname: Raimondo
authors.forename: Ivano
authors.initials: I
authors.lastname: Bilotti
authors.forename: Aldo
authors.initials: A
authors.lastname: Brillante
authors.forename: Raffaele G
authors.initials: RG
authors.lastname: Della Valle
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Venuti