Orientational dynamics of hydrogen‐bonded liquids – A comparative study of dielectric and nuclear magnetic relaxation in n‐butanol‐tetrachloromethane mixtures

Complex dielectric spectra up to 20 GHz are measured at 25°C for n‐butanol tetrachloromethane mixtures. Within this frequency range the spectra can be described by two Debye‐processes. Their relaxation times τ (1) 1 and τ (2) 1 are compared with the hypothetical single‐particle relaxation time of the dipoles τ s 1 estimated from deuteron magnetic relaxation rates in these mixtures. The results indicate a collective nature of the primary relaxation time τ (1) 1 due to cooperative motion of several molecules. Although not accurate in detail, some theoretical models can reproduce major features of the concentration dependence of τ (1) 1 . In these models, τ (1) 1 is coupled to τ s 1 via the Kirkwood correlation factor g 1 which can be determined independently from the static permittivity. There is no obvious interrelation between τ s 1 and the secondary relaxation time τ (2) 1 the nature of which remains puzzling.