压强对苯分子费米共振的影响

测量了在0—13GPa压强下苯分子的拉曼光谱,结果表明:所有拉曼谱带随压强的增加发生蓝移,并伴随某些谱带的劈裂和相对强度的变化;而对于苯分子的ν1+ν6—ν8两费米共振谱带,根据Betran理论,计算出它们的频率间隔Δ0随压强的增加而增大,这是由于合频ν1+ν6频移随压强增加速度大于相应于基频ν8速度的结果,进而导致了费米共振耦合系数ω和强度比Rf/a减小.当压强增加至11GPa时,费米共振现象消失,该现象用高压下相变给予解释.本结果丰富了环境变化对分子费米共振影响的研究内容,对谱线认证、归属有参考价值.

Effect of pressure on the Fermi resonance of benzene

Raman spectra of benzene have been obtained at pressure of 13 GPa. The results shows that with the increase of pressure all the Raman bands blue shift, accompanied with the splitting and change of relative intensity of some spectral bands. For th vibrational Fermi resonance bands v_1 + v_6——v_8, according to the Betran theory, the unperturbed peak separation △_0 increase with pressure,which is due to the ratio of frequency-pressure of the combined ν_1 + ν_6 bands is larger than that of fundamental ν_8 As a consequence, the coupling coefficient ω and the intensity ratio R_(f/a) decrease. The Fermi resonance phenomeno disappears when the pressure is up to 11 Gpa, which can be explaned by high-pressure phase transition method. This report enriches the studies of environmental effect on the Fermi resonance, and provides positive reference value for the spectral certification and assignment.