Coherent vibrational dynamics in sexithiophene films

The coherent vibrational spectroscopy technique has been employed to directly probe in real time strongly coupled modes in sexithiophene polycrystalline films. The excitation source was a recently developed tunable 10-fs optical parametric amplifier. We identify five modes strongly coupled to the lowest electronic transition, with frequencies ω1 = 112 cm−1, ω2 = 299 cm−1, ω3 = 702 cm−1, ω4 = 1040 cm−1,and ω5 = 1454 cm−1. The assignment of these frequencies is discussed,