1,2,4,5-Tetrabromobenzene (TBB), a thermosalient crystal, jumps upon heating because of a temperature-induced phase transition. Due to its thermosalient behavior, TBB may have use as a molecular actuator. However, prior studies have not determined the mechanism[CR1] responsible for the phase transition and observed jumping motion of the crystals. Previous work has found that the structural differences between the low-temperature β phase and the high-temperature γ phase to be too small to explain the observed jumping motion of the crystals. We employed low-frequency Raman spectroscopy (10-250 cm<sup>-1</sup>) to obtain spectra before and after the phase transition to measure phonon modes that may be crucial to both the phase transition and the jumping mechanism. We also used femtosecond stimulated Raman spectroscopy (FSRS) to study the dynamics of these vibrations with femtosecond time-resolution. By using this technique in conjunction with rationally designed pulses, it may be possible to stimulate the modes responsible for driving the phase transition, enabling control of the reaction through light.

Investigating the thermosalient effect of 1,2,4,5-tetrabromobenzene using femtosecond stimulated Raman spectroscopy

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.