Anharmonic coupling between fundamental modes in tetramethylurea

In situ high pressure Raman spectra of tetramethylurea have been measured up to 25 GPa, liquid-solid and solid-solid phase transitions were detected at 0.2 GPa and 7.4 GPa, respectively. An unprecedented spectral phenomenon is the observation of a Fermi resonance between the fundamental modes. An ex...

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Bibliographic Details
Main Authors: Chen, Yuanzheng, Men, Zhiwei, Li, Juntao, Li, Zhanlong, Sun, Shengnan, Sun, Chengling, Gao, Shuqin, Li, Zuowei, Zhou, Mi
Other Authors: School of Materials Science & Engineering
Format: Article
Language:English
Published: 2014
Subjects:
Online Access:https://hdl.handle.net/10356/98746
http://hdl.handle.net/10220/19602
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Institution: Nanyang Technological University
Language: English
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Summary:In situ high pressure Raman spectra of tetramethylurea have been measured up to 25 GPa, liquid-solid and solid-solid phase transitions were detected at 0.2 GPa and 7.4 GPa, respectively. An unprecedented spectral phenomenon is the observation of a Fermi resonance between the fundamental modes. An exponential relationship between the intensity and the frequency difference was concluded. Pressure provides us a new way to study the correlation between Fermi resonance parameters.