Dielectric relaxation measurements on methanol up to the supercritical region

The static permittivity epsilon (0) and the dielectric relaxation time tau (D) have been obtained for methanol over a wide range of temperature and pressure up to 600 K and 21 MPa. The dielectric relaxation time tau (D) decreases with increasing temperature and has little pressure dependence in the liquid state. In the gaseous state, however, tau (D) increases with decreasing density. Since these behaviours are qualitatively the same as those for water, we have successfully applied our model for the dielectric relaxation in water to that in methanol with some appropriate modifications.