Ultrafast IR Spectroscopy Reveals the Structural and Dynamical Heterogeneity in Glassy Materials

Wednesday, May 27, 2020 - 3:00pm

Speaker:  David J. Hoffman, Stanford University

Program Description:

The remarkable properties of glassy materials arise from their complex amorphous structures and dynamics. The heterogeneity of these materials was studied on molecular length scales and picosecond time scales using a combination of polarization-selective IR pump-probe and 2D IR experiments and a vibrational chromophore that is sensitive to local chemical and electrical environments. By monitoring the restricted orientational motion of the chromophore in a polymer, the distribution of sub-nanometer pores could be explored. The same chromophore in a hydrogen-bonding system showed extreme polarization dependence in the 2D line shape, providing evidence for significant dynamical heterogeneity in the supercooled liquid phase.

 

Ultrafast IR Spectroscopy Reveals the Structural and Dynamical Heterogeneity in Glassy Materials
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