Intramolecular energy transport mechanisms were studied by relaxation-assisted two-dimensional infrared (RA 2DIR) spectroscopy method. Vibrational energy propagation in materials is governed by two limiting regimes, diffusive and ballistic. While the diffusive transport is associated with random walk hopping and observed in many molecular systems, the discovery of ballistic energy transport remains relatively new. It involves vibrational states delocalized over the transport region leading to high efficiency constant speed wavepacket propagation.<br/>Oligomers of PEG, perfluoroalkane and alkane chains of various lengths were used in this study.<br/>We have discovered that the efficient ballistic regime is common to molecules with repeating units and thus it has to be taken into account as fundamental part of any energy dissipation process in molecules. Present study sheds light on the contributions of both ballistic and diffusive mechanisms into the energy dissipation within molecules. Switching between two regimes and limiting factors for the transport speed in molecules are discussed. The highest speed of 1320 m/s is detected in linear alkanes.

Energy transport in molecules with repeating units occurs ballistically

249th National Meeting (2015)

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