Raman scattering spectroscopic study of n-tetradecane under high pressure and ambient temperature

The Raman spectroscopy of n-tetradecane was investigated in a Moissanite anvil cell at pressure from 0.1 MPa to 1.4 GPa and ambient temperature. The result shows that the liquid–solid phase transition of n-tetradecane takes place at around 302.8 MPa and the corresponding ΔVm obtained is about −9.6 cm−3/mol. Above 302.8 MPa, the frequencies of CH2 and CH3 symmetric stretching and asymmetric stretching vibration shift to higher wave numbers in a linear manner with increasing pressure, which can be expressed as: νs(CH3) = 0.013P + 2882.0; νas(CH3) = 0.014P + 2961.6; νs(CH2) = 0.013P + 2850.8; νas(CH2) = 0.009P + 2923.2. This relationship indicates that n-tetradecane can be a reliable pressure gauge for the experimental study within the pressure range of 0.3–1.4 GPa.