Anharmonic coupling between fundamental modes in tetramethylurea

Yuanzheng Chen; Zhiwei Men; Juntao Li; Zhanlong Li; Shengnan Sun; Chengling Sun; Shuqin Gao; Zuowei Li; Mi Zhou

doi:10.1063/1.4872159

Anharmonic coupling between fundamental modes in tetramethylurea

J Chem Phys. 2014 Apr 28;140(16):164310. doi: 10.1063/1.4872159.

Authors

Yuanzheng Chen¹, Zhiwei Men², Juntao Li², Zhanlong Li², Shengnan Sun², Chengling Sun², Shuqin Gao², Zuowei Li², Mi Zhou¹

Affiliations

¹ State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, People's Republic of China.
² College of Physics, Jilin University, Changchun130012, People's Republic of China.

PMID: 24784273
DOI: 10.1063/1.4872159

Abstract

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.