Abstract

The vibrational Fermi resonance of two liquids, methanol (CH3OH) and dichloromethane (CH2Cl2), is investigated by measuring changes in the position and intensity of Fermi-coupled Raman bands as a function of pressure, in a diamond anvil cell. The Fermi resonance of interest occurs in the 2900 cm-1 spectral region, where coupling between the CH symmetric stretch fundamental and a CH bend overtone gives rise to two prominent bands. The methanol results reveal a pressure induced transition through exact resonance at 1.25 GPa, where the two coupled states decompose into a pair of fully mixed hybrid bands. In dichloromethane, on the other hand, the two coupled states are driven farther apart and become less mixed with increasing pressure. The Fermi resonance coupling coefficient, W, is found to be constant in each liquid up to pressures exceeding 1 GPa (W ≈ 52.6 and 22.3 cm-1 in CH3OH and CH2Cl2, respectively). The anharmonic shift of the CH bend is about 10 cm-1 in both liquids, determined by comparing the fr...

Full Text

Published Version

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.