TY - JOUR T1 - Phonon Kinetics of Fructose at the Melting Transition JF - J. Phys. Chem. C Y1 - 2021 A1 - A. Davie A1 - F. Vandrevala A1 - S. Dampf A1 - Y. Deng A1 - D. K. George A1 - E. D. Sylvester A1 - T. Korter A1 - E. Einarsson A1 - J. B. Benedict A1 - A. G. Markelz AB -

Terahertz time domain spectroscopy (THz TDS) is used to measure the melting kinetics of fructose molecular crystals. Combining single-crystal anisotropy measurements with density functional calculations, we assign the phonon frequencies and interrogate how specific phonons behave with melting. While nearly all the low-frequency phonons continuously red-shift with heating and melting, the lowest-energy phonon polarized along the c-axis blue-shifts at the melting temperature, suggesting an initial structural change immediately before melting. We find that the kinetics follow a 3D growth model with large activation energies, consistent with previous differential scanning calorimetry (DSC) measurements. The large activation energies indicate that multiple H-bonds must break collectively for the transition. The results suggest the generality of the kinetics for molecular crystals and that THz TDS with picosecond resolution could be used to measure ultrafast kinetics.

 

VL - 125 IS - 22 ER -