Permittivity increments in non-dipolar solvents due to high electric fields

Measurements of the change in relative permittivity (ΔIµ) have been made as a function of applied electric field (E) at 22°C for the non-dipolar liquids n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, cyclohexane, benzene, carbon tetrachloride and carbon disulphide. The measurements were made at fields of up to 2 × 107 V m–1, the ΔIµ being detected via the change in frequency of an oscillator as measured using a computing counter. The range of ΔIµ/E2 values obtained were from about 10 to 30 × 10–20m2V–2. The values were generally larger than could be attributed to the anisotropy of polarizability, particularly for the nearly spherical carbon tetrachloride molecule and much larger than the expected contributions due to electrostriction and the electrocaloric effect. The measured values are undoubtedly made up from a number of effects, including the Kielich local fluctuating intermolecular effects.