Open AccessHigh pressure Raman investigation on the Fermi resonance of biphenyl
Author(s) -
Mi Zhou,
Zhanlong Li,
Guang-Hong Lü,
Dongfei Li,
ChiaChung Sun,
Gao Shu-Qin,
Zuowei Li
Publication year - 2011
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.60.050702
Subject(s) - fermi resonance , raman spectroscopy , resonance (particle physics) , materials science , fermi level , condensed matter physics , biphenyl , intensity (physics) , fermi gamma ray space telescope , phase transition , nuclear magnetic resonance , molecular physics , atomic physics , physics , chemistry , optics , organic chemistry , quantum mechanics , electron
Raman spectra of biphenyl have been obtained under pressures up to 15 GPa. The results indicated that with the increase of pressure, the effect of inter- and intra-molecular π-πconjugation and delocation increases, accompanied by the intensity enhancement of the Raman bands, and blue shift of the frequency. The intensity ratio (Rf/a) of two Fermi resonance bands υ'6 + υ' 1 and υ' 8 decreases, and the frequency difference Δ increases with the pressure. The Fermi resonance phenomenon disappears when the pressure goos up to 8 GPa. Using J.F. Bertran's theory, we obtained the relationship of the inherent frequency difference Δ0 and coupling coefficient ω with pressure. This phenomenon was explained by high-pressure phase transition. The mechanism of high pressure induced Fermi resonance weakening was also discussed.