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Updated: Oct 18, 2025

Ultrafast Time-resolved Near-IR Stimulated Raman Measurements of Functional π-conjugate Systems
Published on: February 10, 2020
Determination of temperature-dependent Fermi resonance in acetonitrile-water binary solution by two-dimensional
Xianwen Cao1, Lu Xing1, Ying Wang1
1Coherent Light and Atomic and Molecular Spectroscopy Laboratory, College of Physics, Jilin University, Changchun 130012, China.
Abstract:
Acetonitrile (AN), as an organic solvent, has a wide range of applications. The C≡N stretching vibration mode (ν2) and the combination mode (ν3 + ν4) are coupled by Fermi resonance (FR). In this work, the phase transition and the interaction mechanism of the 60% AN-water binary solution (AN-Water) were analyzed by calculating FR parameters and two-dimensional correlation Raman spectroscopy (2DCRS). The change in the ν2 band and the base bands ν3 and ν4 caused energy transfer by anharmonic interaction, which led to a change in FR parameters. With a reduced temperature, the energy transfer was caused by microheterogeneity and the energy transfer effect (293-273 K), the phase separation (263-233 K), and the phase transition of AN (223-173 K). The 2DCRS and Gaussian deconvolution provided more information on FR, which revealed the interaction mechanism of the Fermi doublet. The polarity and binding modes of molecules provided a new perspective for analyzing the transmission of electrons and ions in the electrolyte at different temperatures.
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