Related Experiment Video
Updated: May 15, 2026

Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
Characterizing Gateway Modes for Solid-Solid Phase Transitions in Organic Crystals: The Thermosalient 4-DBpFO
Daria Ruth Galimberti1, Xinyue Li1, Maarten W de Dreu1,2
1Radboud University, Institute for Molecules and Materials, Nijmegen 6500 GL, The Netherlands.
Abstract:
We disclose the nature of the 4-DBpFO thermosalient (or "jumping") crystal phase transition 40 cm-1 (i.e., 1.2 THz) "gateway" mode using computed low-frequency Raman spectra (LFRS) benchmarked to experimental spectra and show that it is a coherent/in-phase collective motion of the inner-outer rings. We explore and reveal the roles of anharmonicity, thermal disorder, and volume fluctuations in determining the THz spectral shape. The anharmonic couplings and cell fluctuations appear to be more than just innocent spectators, and indeed, the intermolecular correlations for this mode involve multiple cells. To obtain this information, we use our Activity Weighted Velocities (AWV) method to integrate classical trajectories with the accuracy of hybrid Density Functional Theory (DFT) Raman activities. We demonstrate that this combination effectively computes accurate LFRS and offers a way to predict the Raman activity of thermally disordered systems and entropically stabilized phases, where current methods (harmonic spectra and DFT-Molecular Dynamics) fail.
Related Concept Videos
Phase Transitions
Phase Transitions
Phase Transitions: Melting and Freezing
Phase Transitions: Vaporization and Condensation
Phase Diagram
Phase Diagram

