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Updated: Oct 2, 2025

Interfacial Molecular-level Structures of Polymers and Biomacromolecules Revealed via Sum Frequency Generation Vibrational Spectroscopy
Published on: August 13, 2019
Pressure-induced Fermi resonance between fundamental modes in phthalic anhydride
HaiRui Liu1, YinQi Chen1, Guangtao Liu1
1College of physics, Jilin University, Changchun, 130012, People's Republic of China.
Abstract:
In situhigh-pressure Raman spectra of phthalic anhydride (PA) have been measured up to 16 GPa through diamond anvil cell technique. The results show that all the Raman bands are blue-shifted with the increase of pressure, accompanied by appearance of some new bands. A Fermi resonance phenomenon of the two Raman fundamental modes of PA at 773 cm-1and 801 cm-1is proposed at pressures above 6.6 GPa, where a possible first-order phase transition occurs. The pressure-induced changes of Fermi resonance parameters, e.g., intensity ratio, coupling coefficient and frequency gap of unperturbed transition, are discussed.
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