Pressure dependence of the Raman frequencies for the modes I, II and III at constant temperatures in phase II of benzene

• The Raman frequencies of the modes I, II and III are calculated in phase II of benzene.
• Frequencies are calculated at various pressures at T = 300 K (I, II) and 450 K (III).
• The observed volume data are used to calculate the Raman frequencies.
• The mode Grüneisen parameters decrease as the pressure increases.
• Calculated frequencies are in agreement with the observed data at low pressures.

We study here the pressure dependence of the Raman frequencies for different modes in phase II of benzene at constant temperatures. By using the experimental data for the volume, we calculate the Raman frequency as a function of pressure at constant temperatures through the isothermal mode Grüneisen parameter for the modes studied. Our calculations show that the Raman frequencies predicted, agree well with the observed frequencies for the modes in phase II of benzene. The isothermal mode Grüneisen parameter decreases with the pressure for the Raman modes studied at constant temperatures for benzene II.