Raman spectra characterization of cycloheptane under high pressure

In situ Raman spectra of cycloheptane have been characterized under high pressure generated by diamond anvil cell (DAC) at room temperature. The pressure is up to 17.00 GPa. With the increase of pressure, the cycloheptane experienced the liquid-solid phase transition at 0.53 GPa. During 3.45-5.58 GPa, both the curve of Raman frequence-pressure and FWHM-pressure presented inflexions, indicating a potential solid-solid phase transition of cycloheptane.