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 1.4GPa and ambient temperature. The result shows that the liquid-solid phase transition of n-tetradecane takes place at around 302.8MPa and the corresponding Delta V-m 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: v(s)(CH3)=0.013P+2882.0; v(as)(CH3)=0.014P+2961.6; v(s)(CH2)=0.013P+2850.8; v(as)(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 0.3-1.4GPa. (C) 2008 Elsevier B.V. All rights reserved.